refactor: use sha

Author: MatteoGabriele

.github/workflows/close-stale.yml

@@ -14,7 +14,7 @@ jobs:
   stale:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/stale@v9
+      - uses: actions/stale@5bef64f19d7facfb25b37b414482c7164d639639
         with:
           days-before-stale: 30
           days-before-close: 14