do not run PR + branch checks together

.gitlab-ci.yml

@@ -16,10 +16,16 @@ variables:
 
 .global_trigger_pull_request: &global_trigger_pull_request
   rules:
+    - if: $CI_COMMIT_BRANCH == "develop"
+      when: never
+    - if: $CI_COMMIT_BRANCH == "master"
+      when: never
     - if: $CI_PIPELINE_SOURCE == "external_pull_request_event"
 
 .global_trigger_build_doc: &global_trigger_build_doc
   rules:
+    - if: $CI_PIPELINE_SOURCE == "external_pull_request_event"
+      when: never
     - if: $CI_COMMIT_BRANCH == "develop"
     - if: $CI_COMMIT_TAG =~ /^v/