Update ci_pr-gatekeeper.yml (#12661)

* Update ci_pr-gatekeeper.yml

.github/workflows/ci_pr-gatekeeper.yml

@@ -1,21 +1,12 @@
 name: 'PR Gatekeeper'
 
 on:
-  pull_request:
-    types:
-      [
-        assigned,
-        unassigned,
-        opened,
-        reopened,
-        synchronize,
-        review_requested,
-        review_request_removed
-      ]
   pull_request_review:
+    types: [submitted]
 
 jobs:
   pr-gatekeeper:
+    if: github.event.review.state == 'approved'
     name: PR Gatekeeper
     runs-on: ubuntu-latest
     steps: