add failure catch to bottom of the workflow

This sends failure information to a slack channel

Author: dcharles525

.github/workflows/docker-build-push-dockerhub.yml

@@ -197,3 +197,14 @@ jobs:
       - name: Cleanup
         run: |
           docker compose down
+
+      - name: Notify Slack on Failure
+        if: failure()
+        uses: slackapi/slack-github-action@v1.24.0
+        with:
+          payload: |
+            {
+              "text": ":x: Workflow *${{ github.workflow }}* failed in job *${{ github.job }}*.\nSee: ${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}"
+            }
+        env:
+          SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }}