Update actions/stale digest to 5bef64f (#2428)

Co-authored-by: elastic-renovate-prod[bot] <174716857+elastic-renovate-prod[bot]@users.noreply.github.com>

Author: elastic-renovate-prod[bot]

.github/workflows/stale.yml

@@ -15,7 +15,7 @@ jobs:
 
     steps:
     - name: "Check PRs"
-      uses: actions/stale@28ca1036281a5e5922ead5184a1bbf96e5fc984e # v9
+      uses: actions/stale@5bef64f19d7facfb25b37b414482c7164d639639 # v9
       with:
         repo-token: ${{ secrets.GITHUB_TOKEN }}
         stale-pr-message: |