ci: send a notification of failing tests on the main branch (#1323)

Co-authored-by: William Bergamin <wbergamin@salesforce.com>

Author: zimeg

.github/workflows/tests.yml

@@ -82,3 +82,18 @@ jobs:
           flags: ${{ matrix.python-version }}
           token: ${{ secrets.CODECOV_TOKEN }}
           verbose: true
+  notifications:
+    name: Regression notifications
+    runs-on: ubuntu-latest
+    needs: build
+    if: failure() && github.ref == 'refs/heads/main' && github.event_name != 'workflow_dispatch'
+    steps:
+      - name: Send notifications of failing tests
+        uses: slackapi/slack-github-action@b0fa283ad8fea605de13dc3f449259339835fc52 # v2.1.0
+        with:
+          errors: true
+          webhook: ${{ secrets.SLACK_REGRESSION_FAILURES_WEBHOOK_URL }}
+          webhook-type: webhook-trigger
+          payload: |
+            action_url: "${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}"
+            repository: "${{ github.repository }}"