Clarify why skips allowed

Author: MaxymVlasov

.github/workflows/ci-cd.yml

@@ -521,4 +521,6 @@ jobs:
       uses: re-actors/alls-green@05ac9388f0aebcb5727afa17fcccfecd6f8ec5fe  # v1.2.2
       with:
         jobs: ${{ toJSON(needs) }}
+        # Needed to not fail on skipped 'push' events for the branches in
+        # upstream repository as they already covered by 'pull_request' event
         allowed-skips: lint,tests