Add prettier check job

.gitlab-ci.yml

@@ -22,6 +22,14 @@ checkstyle:
     - ./mvnw -ntp checkstyle:check -Dmaven.repo.local=$MAVEN_USER_HOME
   needs: []
 
+prettier:
+  stage: lint
+  script:
+    - npm install
+    - npm run prettier:check
+  allow_failure: true
+  needs: []
+
 eslint:
   stage: lint
   script: