adjusted github CI

.github/workflows/api-breakage.yml

@@ -0,0 +1,22 @@
+name: API breaking changes
+
+on:
+  pull_request:
+
+jobs:
+  linux:
+    runs-on: ubuntu-latest
+    timeout-minutes: 15
+    container:
+      image: swift:latest
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v4
+      with:
+        fetch-depth: 0
+    # https://github.com/actions/checkout/issues/766
+    - name: Mark the workspace as safe
+      run: git config --global --add safe.directory ${GITHUB_WORKSPACE}
+    - name: API breaking changes
+      run: |
+        swift package diagnose-api-breaking-changes origin/${GITHUB_BASE_REF}

.github/workflows/ci.yaml

@@ -16,7 +16,7 @@ jobs:
     timeout-minutes: 15
     strategy:
       matrix:
-        image: ["swift:5.10", "swiftlang/swift:nightly-6.0-jammy"]
+        image: ["swift:5.10", "swift:6.0"]
 
     container:
       image: ${{ matrix.image }}