Added Monorepo Merge Notice Workflow

This workflow leaves a comment and closes any pull requests
or issues that have been opened in
the repository.

.github/workflows/monorepo-merge-notices.yml

@@ -0,0 +1,32 @@
+name: 'Monorepo Merge Notices'
+on:
+  pull_request:
+    types: [ 'opened' ]
+  issues:
+    types: [ 'opened' ]
+jobs:
+  issue_block:
+    name: 'Block Issues & Pull Requests'
+    runs-on: 'ubuntu-latest'
+    steps:
+      - name: 'Add Merge Notice'
+        uses: 'actions/github-script@v5'
+        with:
+          script: |
+              github.rest.issues.createComment( {
+                issue_number: context.issue.number,
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                body: 'We have merged WooCommerce Blocks into the WooCommerce monorepo. Please open any issues or pull requests \
+                in the woocommerce/woocommerce repository.'
+              } );
+      - name: 'Close'
+        uses: 'actions/github-script@v5'
+        with:
+          script: |
+            octokit.rest.issues.update({
+              issue_number: context.issue.number,
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              state: 'closed'
+            });