[skip ci] Update .gitlab-ci.yml file

.gitlab-ci.yml

+workflow:
+  rules:
+    - if: '$CI_PIPELINE_SOURCE == "web"'
+    - if: $CI_COMMIT_BRANCH && $CI_OPEN_MERGE_REQUESTS && $CI_PIPELINE_SOURCE == "push"
+      when: never
+    - if: '$CI_PIPELINE_SOURCE == "merge_request_event"'
+    - if: '$CI_COMMIT_BRANCH && $CI_OPEN_MERGE_REQUESTS'
+      when: never
+    - if: '$CI_COMMIT_BRANCH'
+    
 stages:
   - license
   - build_and_test
@@ -10,7 +20,6 @@ stages:
   - echo $WOLF_VISION_BRANCH
   - echo $WOLF_ROS_NODE_BRANCH
   - echo $CI_COMMIT_BRANCH
-  - echo $WOLF_ROS_VISION_BRANCH
 
 .preliminaries_template: &preliminaries_definition
   ## Install ssh-agent if not already installed, it is required by Docker.