ci(@nestjs) update travis.yml

Author: kamilmysliwiec

.travis.yml

@@ -6,6 +6,9 @@ addons:
 before_script:
      - export DISPLAY=:99.0
      - sh -e /etc/init.d/xvfb start
+install:
+     - npm install
+     - npm build
 script:
       - npm build
       - npm test