Update merge-upstream.yaml

.github/workflows/merge-upstream.yaml

@@ -5,7 +5,7 @@ on:
     - cron: '23 0/3 * * *'
 
 jobs:
-  merge-upstream:
+  merge_upstream:
     runs-on: ubuntu-latest
     steps: 
       - name: Checkout
@@ -19,3 +19,19 @@ jobs:
           upstream: open-telemetry/opentelemetry-demo
           upstream-branch: main
           branch: main
+  notify-failure:
+    needs: [merge_upstream]
+    if: needs.merge_upstream.result != 'success'
+    runs-on: ubuntu-latest
+    steps:
+    - name: Slack notification
+      env:
+        SLACK_WEBHOOK: "${{ secrets.OTelSlackChannelWebhook }}"
+        SLACK_UNFURL_LINKS: "true"
+      uses: AlexanderWert/[email protected]
+      with:
+        args: |
+          :wave:
+          Auto-merge of the <${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}|elastic/opentelemetry-demo> repository with the upstream failed!
+          Manual resolution of the merge conflicts is required!
+