Update stale-issue.yml (#55)

cron syntax fix

Co-authored-by: Michael Graeb <[email protected]>

Author: KaibaLopez

.github/workflows/stale-issue.yml

@@ -3,7 +3,7 @@ name: "Close stale issues"
 # Controls when the action will run.
 on:
   schedule:
-    - cron: "/30 * * * *"
+    - cron: "*/30 * * * *"
 
 jobs:
   cleanup: