Update .gitlab-ci.yml

.gitlab-ci.yml

 build-angular-ui:
-  stage: build
+  stage: build-angular-ui
   image: trion/ng-cli
   before_script:
     - npm install -g --save-dev @angular/cli@latest
@@ -9,7 +9,7 @@ build-angular-ui:
     - ng build --prod
     
 build-ui-docker:
-  stage: build
+  stage: build-ui-docker
   image: docker:19.03.1
   services:
     - docker:19.03.1-dind