Potential fix for code scanning alert no. 11: Workflow does not contain permissions (#580)

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

Author: Slashgear

.github/workflows/deploy-cleanup.yml

@@ -1,4 +1,6 @@
 name: 🧹 Cleanup
+permissions:
+  contents: read
 on:
   pull_request:
     types: [closed]