CI: Process stale issues four times per day (#116857)

Author: hugovk

.github/workflows/stale.yml

@@ -2,7 +2,7 @@ name: Mark stale pull requests
 
 on:
   schedule:
-  - cron: "0 */12 * * *"
+  - cron: "0 */6 * * *"
 
 permissions:
   pull-requests: write