Run action every hour

Author: Matt Gaunt

.github/workflows/stale-prs.yml

@@ -2,7 +2,7 @@ name: 'Close stale PRs'
 on:
   workflow_dispatch:
   schedule:
-    - cron: '0 0 * * *'
+    - cron: '0 * * * *'
 
 permissions:
   pull-requests: write