feature(core): refactor GitLab CI build rules structure

gitlab-ci.yml

@@ -11,7 +11,7 @@ stages:
   - build
   - deploy
 
-.template: &build-rules
+.build-rules:
   rules:
     - if: '$CI_PIPELINE_SOURCE == "merge_request_event" || $CI_COMMIT_REF_NAME == "devel"'
       when: always
@@ -65,7 +65,7 @@ stages:
         DEPLOY_HOST: $PRODUCTION_DEPLOY_HOST
 
 build web frontend:
-  <<: *build-rules
+  extends: .build-rules
   image: node:latest
   artifacts:
     paths:
@@ -84,7 +84,7 @@ build web frontend:
     - npm run build
 
 build web backend:
-  <<: *build-rules
+  extends: .build-rules
   image: composer:latest
   artifacts:
     paths: