ci: confirm expected autogenerated reference exists

Author: zimeg

.github/workflows/ci-build.yml

@@ -53,6 +53,12 @@ jobs:
           pip install "SQLAlchemy>=1.4,<2"
           PYTHONPATH=$PWD:$PYTHONPATH pytest tests/slack_sdk/oauth/installation_store/test_sqlalchemy.py
           PYTHONPATH=$PWD:$PYTHONPATH pytest tests/slack_sdk/oauth/state_store/test_sqlalchemy.py
+      - name: Confirm expected autogenerated reference exists
+        run: |
+          python -m venv .venv
+          source .venv/bin/activate
+          bash ./scripts/generate_api_docs.sh
+          git diff --quiet
       - name: Upload test results to Codecov
         if: ${{ !cancelled() }}
         uses: codecov/test-results-action@47f89e9acb64b76debcd5ea40642d25a4adced9f # v1.1.1