chore: Automate closing of stale issues

  This commit updates the GitHub Actions workflow to automatically manage and close stale issues that are awaiting a user response.

  The workflow now performs the following actions:
   - Marks issues with the "status:awaiting user response" label as stale after 7 days of inactivity.
   - Posts a comment notifying that the issue will be closed if no further activity occurs.
   - Closes the issue if there is no activity for an additional 2 days.

PiperOrigin-RevId: 788946450

Author: amirh

.github/workflows/stale.yml

@@ -0,0 +1,31 @@
+# This workflow warns and then closes issues that have had no activity for a specified amount of time.
+name: Mark and close stale issues
+
+on:
+  schedule:
+  # Scheduled to run at 1:30 UTC everyday
+  - cron: '30 1 * * *'
+
+jobs:
+  stale:
+
+    runs-on: ubuntu-latest
+    permissions:
+      issues: write
+
+    steps:
+    - uses: actions/stale@v5
+      with:
+        repo-token: ${{ secrets.GITHUB_TOKEN }}
+        days-before-issue-stale: 7
+        days-before-issue-close: 2
+        stale-issue-label: "status:stale"
+        close-issue-reason: not_planned
+        any-of-labels: "status:awaiting user response"
+        stale-issue-message: >
+          This issue has been marked as stale because it has been open for 7 days with no activity. It will be closed in 2 days if no further activity occurs.
+        close-issue-message: >
+          This issue was closed because it has been inactive for 9 days.
+          Please post a new issue if you need further assistance. Thanks!
+        # Label that can be assigned to issues to exclude them from being marked as stale
+        exempt-issue-labels: 'override-stale'