Use stale action

.github/workflows/stale.yml

@@ -0,0 +1,27 @@
+name: Mark stale issues and pull requests
+
+on:
+  schedule:
+    # Once every day at midnight UTC
+    - cron: "0 0 * * *"
+
+jobs:
+  Stale:
+    runs-on: ubuntu-latest
+    permissions:
+      issues: write
+      pull-requests: write
+    steps:
+    - uses: actions/stale@v9
+      with:
+        repo-token: ${{ secrets.GITHUB_TOKEN }}
+        days-before-stale: 21
+        days-before-close: 7
+        stale-issue-message: >
+          This issue has been automatically marked as stale because it has not had
+          recent activity. It will be closed if no further activity occurs.
+        stale-pr-message: >
+          This pull request has been automatically marked as stale because it has not had
+          recent activity. It will be closed if no further activity occurs.
+        stale-issue-label: 'stale'
+        stale-pr-label: 'stale'