#2: added client prefix to stages in client yml file

.gitlab/client.gitlab-ci.yml

 image: node:10
 
 install:
-  stage: install
+  stage: client-install
   script:
     - cd client
     - npm install
@@ -14,7 +14,7 @@ install:
       - client/node_modules/
 
 linting:
-  stage: test
+  stage: client-test
   script:
     - cd client
     - npm run lint
@@ -22,7 +22,7 @@ linting:
     - install
 
 test:unit:
-  stage: test
+  stage: client-test
   script:
     - cd client
     - npm run test:coverage