chore: automate description requests when notable change label is added

Author: danielleadams

.github/workflows/comment-labeled.yml

@@ -10,6 +10,11 @@ env:
     This issue/PR was marked as stalled, it will be automatically closed in 30 days.
     If it should remain open, please leave a comment explaining why it should remain open.
   FAST_TRACK_MESSAGE: Fast-track has been requested by @${{ github.actor }}. Please 👍 to approve.
+  NOTABLE_CHANGE_MESSAGE: The notable-changes label has been added by @${{ github.actor }}.
+    Please include your text below if you'd like to include a more detailed summary in the changelog.
+    ```
+    [Insert here]
+    ```
 
 permissions:
   contents: read
@@ -38,3 +43,14 @@ jobs:
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         run: gh pr comment ${{ github.event.pull_request.number }} --repo ${{ github.repository }} --body "$FAST_TRACK_MESSAGE"
+
+  notable-change:
+    permissions:
+      pull-requests: write
+    if: github.repository == 'nodejs/node' && github.event_name == 'pull_request_target' && github.event.label.name == 'notable-change'
+    runs-on: ubuntu-latest
+    steps:
+      - name: Add notable change description
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: gh pr comment ${{ github.event.pull_request.number }} --repo ${{ github.repository }} --body "$NOTABLE_CHANGE_MESSAGE"