feat: add merge request in gitlab-ci

config/.gitlab/check_merge_request.yml

@@ -3,6 +3,8 @@
   needs: ['Build Drupal']
   tags:
     - spud
+  rules:
+    - if: $CI_MERGE_REQUEST_ID
 
 PHPCS:
   stage: Code quality PHP 7.4
@@ -25,8 +27,3 @@ PHPStan:
       web/modules/contrib_project/ > phpstan.json
   artifacts:
     paths: [phpstan.json]
-
-workflow:
-  rules:
-    # Execute jobs in merge request context.
-    - if: $CI_MERGE_REQUEST_ID