add codecov config

.codecov.yml

@@ -0,0 +1,37 @@
+coverage:
+  precision: 2
+  round: down
+  range: 70...100
+
+  status:
+    project: 
+      default:
+        threshold: 1% # allow this much decrease on project
+    changes: false
+
+comment:
+  layout: "reach, diff, files"
+  behavior: default  # update if exists else create new
+
+ignore:
+  - "api/"
+  - "*.md"
+  - "*.rst"
+  - "cmd/"
+  - "contrib/"
+  - "docs/"
+  - "networks/"
+  - "proto/"
+  - "scripts/"
+  - "thrid_party/"
+  - "docker/"
+  - "client/"
+  - "custom/"
+  - "**/cli"
+  - "**/rest"
+  - "**/*.pb.go"
+  - "**/*.pulsar.go"
+  - "**/*.pb.gw.go"
+  - "**/test_utils.go"
+  - "**/module.go"
+  - "x/ibc/testing"