Fix permissions for label Ready to Merge on approved pull requests

.github/workflows/pr-label-on-approved.yml

@@ -1,5 +1,11 @@
 on: pull_request_review
 name: Label approved pull requests
+
+permissions:
+  contents: read          # Required for checking changed files
+  pull-requests: write    # Required for labeling PRs
+  issues: write           # Required for adding/removing labels
+
 jobs:
   labelWhenApproved:
     if: ${{ github.repository_owner == 'armbian' }}