Use an alternative keep-alive workflow

Author: dotdoom

.github/workflows/delern.yml

@@ -34,4 +34,4 @@ jobs:
           commit_message: "Automatic Realtime Database backup"
           repository: database-storage
 
-      - uses: gautamkrishnar/keepalive-workflow@master
+      - uses: liskin/gh-workflow-keepalive@v1