ci(labeler): check every 6 hours instead of every 5 minutes

.github/workflows/label.yml

@@ -1,7 +1,7 @@
 name: Pull Request Labeler
 on:
   schedule:
-    - cron: '*/5 * * * *'
+    - cron: '0 */6 * * *'
 jobs:
   labeler:
     runs-on: ubuntu-latest