feat(ci): using yarn for CI instead of npm
feat(ci): using yarn for CI instead of npm

StephanGieffers/ionic-fb-playground,kojinkai/predictor-ionic,marcoturi/ionic2-boilerplate,marcoturi/ionic2-boilerplate,kojinkai/predictor-ionic,marcoturi/ionic-boilerplate,StephanGieffers/ionic-fb-playground,kojinkai/predictor-ionic,StephanGieffers/ionic-fb-playground,marcoturi/ionic2-boilerplate,marcoturi/ionic-boilerplate,marcoturi/ionic-boilerplate,marcoturi/ionic-boilerplate,kojinkai/predictor-ionic,marcoturi/ionic2-boilerplate,StephanGieffers/ionic-fb-playground