Adding post deploy step needed for slack notifications (#11654)

Co-authored-by: Doug White <[email protected]>

.github/workflows/post-deploy-slack-notification.yml

@@ -0,0 +1,19 @@
+name: Post Deploy
+
+on:
+  workflow_run:
+    workflows: [Deploy]
+    branches: [main, val, production]
+    types: [completed]
+
+jobs:
+  on-success:
+    runs-on: ubuntu-latest
+    if: ${{ github.event.workflow_run.conclusion == 'success' }}
+    steps:
+      - run: echo 'The triggering workflow passed'
+  on-failure:
+    runs-on: ubuntu-latest
+    if: ${{ github.event.workflow_run.conclusion == 'failure' }}
+    steps:
+      - run: echo 'The triggering workflow failed'