build: harden stale.yml permissions

Signed-off-by: Alex <aleksandrosansan@gmail.com>

.github/workflows/stale.yml

@@ -3,8 +3,13 @@ on:
   schedule:
     - cron: "30 0 * * *"
 
+permissions: {}
 jobs:
   close-issues:
+    permissions:
+      issues: write # to close stale issues (actions/stale)
+      pull-requests: write # to close stale PRs (actions/stale)
+
     runs-on: ubuntu-latest
     steps:
       - uses: actions/stale@v3