Add code coverage report

.github/workflows/ci.yaml

@@ -38,7 +38,9 @@ jobs:
         env:
           CGO_ENABLED: 0
       - name: go test
-        run: go test -tags nolibopusfile ./... -v -race
+        run: go test -tags nolibopusfile ./... -v -race -coverprofile=coverage.txt -covermode=atomic
+      - uses: codecov/codecov-action@v1
+        if: matrix.go == '1.15'
       - name: go test without CGO
         run: go test . pkg/... -v
         env:

codecov.yml

@@ -0,0 +1,10 @@
+coverage:
+  status:
+    project:
+      default:
+        # Allow decreasing 2% of total coverage to avoid noise.
+        threshold: 2%
+    patch: off
+
+ignore:
+  - "examples/*"