Add example of different packages per python version

This is me trying to add an example of something that I was seeing not work as
I expected internally and making sure it wasn't something specific to our repo.
In our usecase we actually have a package interal that only works up to a specific
version of python.

However I keep getting this error when using py_binary or py_test.

```
ERROR: /private/var/tmp/_bazel_schuettm/e053d0eaf0a843e9f76bdb61766af4b7/external/rules_python++pip+pypi_3_10_only/flask/BUILD.bazel:5:12: configurable attribute "actual" in @@rules_python++pip+pypi_3_10_only//flask:pkg doesn't match this configuration: No matching wheel for current configuration's Python version.

The current build configuration's Python version doesn't match any of the Python
wheels available for this distribution. This distribution supports the following Python
configuration settings:
    //_config:is_python_3.11

To determine the current configuration's Python version, run:
    `bazel config <config id>` (shown further below)

and look for one of:
    @@rules_python+//python/config_settings:python_version
    @@rules_python+//python/config_settings:pip_whl
    @@rules_python+//python/config_settings:pip_whl_glibc_version
    @@rules_python+//python/config_settings:pip_whl_muslc_version
    @@rules_python+//python/config_settings:pip_whl_osx_arch
    @@rules_python+//python/config_settings:pip_whl_osx_version
    @@rules_python+//python/config_settings:py_freethreaded
    @@rules_python+//python/config_settings:py_linux_libc

If the value is missing, then the default value is being used, see documentation:
https://rules-python.readthedocs.io/en/latest/api/rules_python/python/config_settings

This instance of @@rules_python++pip+pypi_3_10_only//flask:pkg has configuration identifier e62ee83. To inspect its configuration, run: bazel config e62ee83.

For more help, see https://bazel.build/docs/configurable-attributes#faq-select-choose-condition.

Use --verbose_failures to see the command lines of failed build steps.
ERROR: Analysis of target '//tests:my_lib_3_10_only_test' failed; build aborted: Analysis failed
INFO: Elapsed time: 0.197s, Critical Path: 0.02s
INFO: 2 processes: 2 internal.
ERROR: Build did NOT complete successfully
//tests:test_versions                                                 NO STATUS

Executed 0 out of 1 test: 1 was skipped.
```

Following the directions hasn't helped me but maybe it makes more sense to someone else.

examples/multi_python_versions/MODULE.bazel

@@ -36,6 +36,7 @@ use_repo(
 
 pip = use_extension("@rules_python//python/extensions:pip.bzl", "pip")
 use_repo(pip, "pypi")
+use_repo(pip, "pypi_3_10_only")
 pip.parse(
     hub_name = "pypi",
     python_version = "3.8",
@@ -56,6 +57,11 @@ pip.parse(
     python_version = "3.11",
     requirements_lock = "//requirements:requirements_lock_3_11.txt",
 )
+pip.parse(
+    hub_name = "pypi_3_10_only",
+    python_version = "3.11",
+    requirements_lock = "//requirements:requirements_lock_3_10_only.txt",
+)
 
 # example test dependencies
 bazel_dep(name = "rules_shell", version = "0.2.0", dev_dependency = True)

examples/multi_python_versions/libs/my_310_only_lib/BUILD.bazel

@@ -0,0 +1,11 @@
+load("@pypi_3_10_only//:requirements.bzl", "requirement")
+load("@rules_python//python:py_library.bzl", "py_library")
+
+py_library(
+    name = "my_310_only_lib",
+    srcs = ["__init__.py"],
+    visibility = ["@//tests:__pkg__"],
+    deps = [
+        requirement("flask")
+    ],
+)

examples/multi_python_versions/libs/my_310_only_lib/__init__.py

@@ -0,0 +1,19 @@
+# Copyright 2023 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import flask
+
+
+# def flask_is_for_python_version(sanitized_version_check):
+#     return f"pypi_{sanitized_version_check}_flask" in websockets.__file__

examples/multi_python_versions/libs/my_lib/BUILD.bazel

@@ -5,5 +5,7 @@ py_library(
     name = "my_lib",
     srcs = ["__init__.py"],
     visibility = ["@//tests:__pkg__"],
-    deps = [requirement("websockets")],
+    deps = [
+        requirement("websockets")
+    ],
 )

examples/multi_python_versions/requirements/BUILD.bazel

@@ -21,6 +21,12 @@ compile_pip_requirements_3_10(
     requirements_txt = "requirements_lock_3_10.txt",
 )
 
+compile_pip_requirements_3_10(
+    name = "requirements_3_10_only",
+    src = "requirements_3_10_only.in",
+    requirements_txt = "requirements_lock_3_10_only.txt",
+)
+
 compile_pip_requirements_3_11(
     name = "requirements_3_11",
     src = "requirements.in",

examples/multi_python_versions/requirements/requirements_3_10_only.in

@@ -0,0 +1 @@
+flask

examples/multi_python_versions/requirements/requirements_lock_3_10_only.txt

@@ -0,0 +1,95 @@
+#
+# This file is autogenerated by pip-compile with Python 3.10
+# by the following command:
+#
+#    bazel run //requirements:requirements_3_10_only.update
+#
+blinker==1.9.0 \
+    --hash=sha256:b4ce2265a7abece45e7cc896e98dbebe6cead56bcf805a3d23136d145f5445bf \
+    --hash=sha256:ba0efaa9080b619ff2f3459d1d500c57bddea4a6b424b60a91141db6fd2f08bc
+    # via flask
+click==8.1.8 \
+    --hash=sha256:63c132bbbed01578a06712a2d1f497bb62d9c1c0d329b7903a866228027263b2 \
+    --hash=sha256:ed53c9d8990d83c2a27deae68e4ee337473f6330c040a31d4225c9574d16096a
+    # via flask
+flask==3.1.0 \
+    --hash=sha256:5f873c5184c897c8d9d1b05df1e3d01b14910ce69607a117bd3277098a5836ac \
+    --hash=sha256:d667207822eb83f1c4b50949b1623c8fc8d51f2341d65f72e1a1815397551136
+    # via -r requirements/requirements_3_10_only.in
+itsdangerous==2.2.0 \
+    --hash=sha256:c6242fc49e35958c8b15141343aa660db5fc54d4f13a1db01a3f5891b98700ef \
+    --hash=sha256:e0050c0b7da1eea53ffaf149c0cfbb5c6e2e2b69c4bef22c81fa6eb73e5f6173
+    # via flask
+jinja2==3.1.5 \
+    --hash=sha256:8fefff8dc3034e27bb80d67c671eb8a9bc424c0ef4c0826edbff304cceff43bb \
+    --hash=sha256:aba0f4dc9ed8013c424088f68a5c226f7d6097ed89b246d7749c2ec4175c6adb
+    # via flask
+markupsafe==3.0.2 \
+    --hash=sha256:0bff5e0ae4ef2e1ae4fdf2dfd5b76c75e5c2fa4132d05fc1b0dabcd20c7e28c4 \
+    --hash=sha256:0f4ca02bea9a23221c0182836703cbf8930c5e9454bacce27e767509fa286a30 \
+    --hash=sha256:1225beacc926f536dc82e45f8a4d68502949dc67eea90eab715dea3a21c1b5f0 \
+    --hash=sha256:131a3c7689c85f5ad20f9f6fb1b866f402c445b220c19fe4308c0b147ccd2ad9 \
+    --hash=sha256:15ab75ef81add55874e7ab7055e9c397312385bd9ced94920f2802310c930396 \
+    --hash=sha256:1a9d3f5f0901fdec14d8d2f66ef7d035f2157240a433441719ac9a3fba440b13 \
+    --hash=sha256:1c99d261bd2d5f6b59325c92c73df481e05e57f19837bdca8413b9eac4bd8028 \
+    --hash=sha256:1e084f686b92e5b83186b07e8a17fc09e38fff551f3602b249881fec658d3eca \
+    --hash=sha256:2181e67807fc2fa785d0592dc2d6206c019b9502410671cc905d132a92866557 \
+    --hash=sha256:2cb8438c3cbb25e220c2ab33bb226559e7afb3baec11c4f218ffa7308603c832 \
+    --hash=sha256:3169b1eefae027567d1ce6ee7cae382c57fe26e82775f460f0b2778beaad66c0 \
+    --hash=sha256:3809ede931876f5b2ec92eef964286840ed3540dadf803dd570c3b7e13141a3b \
+    --hash=sha256:38a9ef736c01fccdd6600705b09dc574584b89bea478200c5fbf112a6b0d5579 \
+    --hash=sha256:3d79d162e7be8f996986c064d1c7c817f6df3a77fe3d6859f6f9e7be4b8c213a \
+    --hash=sha256:444dcda765c8a838eaae23112db52f1efaf750daddb2d9ca300bcae1039adc5c \
+    --hash=sha256:48032821bbdf20f5799ff537c7ac3d1fba0ba032cfc06194faffa8cda8b560ff \
+    --hash=sha256:4aa4e5faecf353ed117801a068ebab7b7e09ffb6e1d5e412dc852e0da018126c \
+    --hash=sha256:52305740fe773d09cffb16f8ed0427942901f00adedac82ec8b67752f58a1b22 \
+    --hash=sha256:569511d3b58c8791ab4c2e1285575265991e6d8f8700c7be0e88f86cb0672094 \
+    --hash=sha256:57cb5a3cf367aeb1d316576250f65edec5bb3be939e9247ae594b4bcbc317dfb \
+    --hash=sha256:5b02fb34468b6aaa40dfc198d813a641e3a63b98c2b05a16b9f80b7ec314185e \
+    --hash=sha256:6381026f158fdb7c72a168278597a5e3a5222e83ea18f543112b2662a9b699c5 \
+    --hash=sha256:6af100e168aa82a50e186c82875a5893c5597a0c1ccdb0d8b40240b1f28b969a \
+    --hash=sha256:6c89876f41da747c8d3677a2b540fb32ef5715f97b66eeb0c6b66f5e3ef6f59d \
+    --hash=sha256:6e296a513ca3d94054c2c881cc913116e90fd030ad1c656b3869762b754f5f8a \
+    --hash=sha256:70a87b411535ccad5ef2f1df5136506a10775d267e197e4cf531ced10537bd6b \
+    --hash=sha256:7e94c425039cde14257288fd61dcfb01963e658efbc0ff54f5306b06054700f8 \
+    --hash=sha256:846ade7b71e3536c4e56b386c2a47adf5741d2d8b94ec9dc3e92e5e1ee1e2225 \
+    --hash=sha256:88416bd1e65dcea10bc7569faacb2c20ce071dd1f87539ca2ab364bf6231393c \
+    --hash=sha256:88b49a3b9ff31e19998750c38e030fc7bb937398b1f78cfa599aaef92d693144 \
+    --hash=sha256:8c4e8c3ce11e1f92f6536ff07154f9d49677ebaaafc32db9db4620bc11ed480f \
+    --hash=sha256:8e06879fc22a25ca47312fbe7c8264eb0b662f6db27cb2d3bbbc74b1df4b9b87 \
+    --hash=sha256:9025b4018f3a1314059769c7bf15441064b2207cb3f065e6ea1e7359cb46db9d \
+    --hash=sha256:93335ca3812df2f366e80509ae119189886b0f3c2b81325d39efdb84a1e2ae93 \
+    --hash=sha256:9778bd8ab0a994ebf6f84c2b949e65736d5575320a17ae8984a77fab08db94cf \
+    --hash=sha256:9e2d922824181480953426608b81967de705c3cef4d1af983af849d7bd619158 \
+    --hash=sha256:a123e330ef0853c6e822384873bef7507557d8e4a082961e1defa947aa59ba84 \
+    --hash=sha256:a904af0a6162c73e3edcb969eeeb53a63ceeb5d8cf642fade7d39e7963a22ddb \
+    --hash=sha256:ad10d3ded218f1039f11a75f8091880239651b52e9bb592ca27de44eed242a48 \
+    --hash=sha256:b424c77b206d63d500bcb69fa55ed8d0e6a3774056bdc4839fc9298a7edca171 \
+    --hash=sha256:b5a6b3ada725cea8a5e634536b1b01c30bcdcd7f9c6fff4151548d5bf6b3a36c \
+    --hash=sha256:ba8062ed2cf21c07a9e295d5b8a2a5ce678b913b45fdf68c32d95d6c1291e0b6 \
+    --hash=sha256:ba9527cdd4c926ed0760bc301f6728ef34d841f405abf9d4f959c478421e4efd \
+    --hash=sha256:bbcb445fa71794da8f178f0f6d66789a28d7319071af7a496d4d507ed566270d \
+    --hash=sha256:bcf3e58998965654fdaff38e58584d8937aa3096ab5354d493c77d1fdd66d7a1 \
+    --hash=sha256:c0ef13eaeee5b615fb07c9a7dadb38eac06a0608b41570d8ade51c56539e509d \
+    --hash=sha256:cabc348d87e913db6ab4aa100f01b08f481097838bdddf7c7a84b7575b7309ca \
+    --hash=sha256:cdb82a876c47801bb54a690c5ae105a46b392ac6099881cdfb9f6e95e4014c6a \
+    --hash=sha256:cfad01eed2c2e0c01fd0ecd2ef42c492f7f93902e39a42fc9ee1692961443a29 \
+    --hash=sha256:d16a81a06776313e817c951135cf7340a3e91e8c1ff2fac444cfd75fffa04afe \
+    --hash=sha256:d8213e09c917a951de9d09ecee036d5c7d36cb6cb7dbaece4c71a60d79fb9798 \
+    --hash=sha256:e07c3764494e3776c602c1e78e298937c3315ccc9043ead7e685b7f2b8d47b3c \
+    --hash=sha256:e17c96c14e19278594aa4841ec148115f9c7615a47382ecb6b82bd8fea3ab0c8 \
+    --hash=sha256:e444a31f8db13eb18ada366ab3cf45fd4b31e4db1236a4448f68778c1d1a5a2f \
+    --hash=sha256:e6a2a455bd412959b57a172ce6328d2dd1f01cb2135efda2e4576e8a23fa3b0f \
+    --hash=sha256:eaa0a10b7f72326f1372a713e73c3f739b524b3af41feb43e4921cb529f5929a \
+    --hash=sha256:eb7972a85c54febfb25b5c4b4f3af4dcc731994c7da0d8a0b4a6eb0640e1d178 \
+    --hash=sha256:ee55d3edf80167e48ea11a923c7386f4669df67d7994554387f84e7d8b0a2bf0 \
+    --hash=sha256:f3818cb119498c0678015754eba762e0d61e5b52d34c8b13d770f0719f7b1d79 \
+    --hash=sha256:f8b3d067f2e40fe93e1ccdd6b2e1d16c43140e76f02fb1319a05cf2b79d99430 \
+    --hash=sha256:fcabf5ff6eea076f859677f5f0b6b5c1a51e70a376b0579e0eadef8db48c6b50
+    # via
+    #   jinja2
+    #   werkzeug
+werkzeug==3.1.3 \
+    --hash=sha256:54b78bf3716d19a65be4fceccc0d1d7b89e608834989dfae50ea87564639213e \
+    --hash=sha256:60723ce945c19328679790e3282cc758aa4a6040e4bb330f53d30fa546d44746
+    # via flask

examples/multi_python_versions/tests/BUILD.bazel

@@ -78,6 +78,13 @@ py_test_3_10(
     deps = ["//libs/my_lib"],
 )
 
+py_test_3_10(
+    name = "my_lib_3_10_only_test",
+    srcs = ["my_lib_test.py"],
+    main = "my_lib_test.py",
+    deps = ["//libs/my_310_only_lib"],
+)
+
 py_test_3_11(
     name = "my_lib_3_11_test",
     srcs = ["my_lib_test.py"],