Update action crons to avoid top of hour runs (#19035)

Author: heiskr

.github/workflows/ping-staging-apps.yml

@@ -6,7 +6,7 @@ name: Ping staging apps
 
 on:
   schedule:
-    - cron: '*/20 * * * *' # every twenty minutes
+    - cron: '10,30,50 * * * *' # every twenty minutes
 
 jobs:
   ping_staging_apps:

.github/workflows/repo-sync.yml

@@ -18,7 +18,7 @@ name: Repo Sync
 on:
   workflow_dispatch:
   schedule:
-    - cron: '*/15 * * * *' # every 15 minutes
+    - cron: '10,25,40,55 * * * *' # every 15 minutes
 
 jobs:
   close-invalid-repo-sync: