ci: update Decision task to use level 3 on push (#161)

Author: ahal

.taskcluster.yml

@@ -95,7 +95,7 @@ tasks:
               level:
                   $if: 'isPullRequest || tasks_for == "pr-action"'
                   then: "1"
-                  else: "1"
+                  else: "3"
           in:
               $if: >
                   tasks_for in ["action", "pr-action", "cron"]