chore(*): update travis to run with ChromeHeadless

Author: nrobakova

projects/igniteui-angular/karma.conf.js

@@ -38,7 +38,7 @@ module.exports = function (config) {
     colors: true,
     logLevel: config.LOG_INFO,
     autoWatch: true,
-    browsers: ['Chrome'],
+    browsers: ['ChromeHeadless'],
     singleRun: false
   });
 };