Add mocha to .gitlab-ci.yml

Signed-off-by: João Victor Risso <jvtr12@c3sl.ufpr.br>

.gitlab-ci.yml

@@ -4,6 +4,7 @@ stages:
 before_script:
   - npm install
   - npm install --global gulp-cli
+  - npm install --global mocha
 
 run_tests:
   stage: test