stale: Use github token and add permission

.github/workflows/stale.yml

@@ -2,16 +2,17 @@ name: "Close stale PR"
 on:
   schedule:
   - cron: "0 0 * * *"
-
   workflow_dispatch:
 
 jobs:
   stale:
+    permissions:
+      pull-requests: write
     runs-on: ubuntu-latest
     steps:
     - uses: actions/stale@v9
       with:
-        repo-token:  ${{ secrets.FLATHUBBOT_TOKEN }}
+        repo-token: ${{ secrets.GITHUB_TOKEN }}
         stale-pr-message: "This PR hasn't received any updates in a year and will be automatically closed in 30 days. If you still plan to work on this please comment or re-open the PR."
         days-before-stale: -1
         days-before-close: -1