Potential fix for code scanning alert no. 8: Workflow does not contain permissions

Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com>

.github/workflows/stale.yml

@@ -1,4 +1,8 @@
 name: 'Close stale issues and PRs'
+permissions:
+  contents: read
+  issues: write
+  pull-requests: write
 on:
   schedule:
     - cron: '0 0 1 */6 *'