add test coverage as comment in PR

Author: marceljk

.github/workflows/ci.yaml

@@ -48,4 +48,18 @@ jobs:
       - name: Check GoReleaser
         uses: goreleaser/goreleaser-action@v6
         with:
-          args: check
+          args: check
+
+  code_coverage:
+    name: "Code coverage report"
+    if: github.event_name == 'pull_request' # Do not run when workflow is triggered by push to main branch
+    runs-on: ubuntu-latest
+    needs: main
+    permissions:
+      contents: read
+      actions: read  # to download code coverage results from "main" job
+      pull-requests: write # write permission needed to comment on PR
+    steps:
+      - uses: fgrosse/[email protected]
+        with:
+          coverage-file-name: "coverage.out"