[Stale workflow] Pin action hash for action version

Pinning action hash version for Stale Github Action

Author: mariedm

.github/workflows/stale.yml

@@ -13,7 +13,7 @@ jobs:
   stale:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/stale@v9
+      - uses: actions/stale@5bef64f19d7facfb25b37b414482c7164d639639 # v9.1.0
         with:
           repo-token: ${{ secrets.GITHUB_TOKEN }}
           stale-issue-message: |