Clean up stale issues with GitHub stale action (#6996)

Author: cknitt

.github/stale.yml

@@ -0,0 +1,20 @@
+name: 'Close stale issues'
+
+on:
+  schedule:
+    - cron: '30 1 * * *'
+
+permissions:
+  issues: write
+
+jobs:
+  stale:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/stale@v9
+        with:
+          debug-only: true # dry-run
+          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. Thank you for your contributions.'
+          stale-issue-label: stale
+          days-before-stale: 120
+          days-before-close: 7