use source branch name

.gitlab-ci.yml

@@ -15,7 +15,7 @@ build-dev:
     - echo $CI_PIPELINE_SOURCE
     - |- 
           if [[ $CI_PIPELINE_SOURVE == "merge_request_event" ]]; then
-              echo "VUE_APP_VERSION_LABEL=merge-request" >> .env.dev_server
+              echo "VUE_APP_VERSION_LABEL=$CI_MERGE_REQUEST_SOURCE_BRANCH_NAME" >> .env.dev_server
           else 
               echo "VUE_APP_VERSION_LABEL=$CI_COMMIT_BRANCH" >> .env.dev_server
           fi