Migrate slack notifications to GChat (2nd attempt)

Closes gh-15667

.github/workflows/pr-build-workflow.yml

@@ -42,3 +42,13 @@ jobs:
           name: docs
           path: docs/build/site
           overwrite: true
+  send-notification:
+    name: Send Notification
+    needs: [ build, generate-docs ]
+    if: ${{ failure() && github.event.pull_request.user.login == 'dependabot[bot]' && github.repository == 'spring-projects/spring-security' }}
+    runs-on: ubuntu-latest
+    steps:
+      - name: Send Notification
+        uses: spring-io/spring-security-release-tools/.github/actions/send-notification@v1
+        with:
+          webhook-url: ${{ secrets.SPRING_SECURITY_CI_GCHAT_WEBHOOK_URL }}