chore(package.json): require newer karma-dart
chore(package.json): require newer karma-dart

This is needed for PR 1375.

SibuStephen/angular.dart,hitesh97/angular.dart,trinarytree/angular.dart,winstonewert/angular.dart,rkirov/angular.dart,hitesh97/angular.dart,winstonewert/angular.dart,SibuStephen/angular.dart,ronlobo/angular.dart,SibuStephen/angular.dart,winstonewert/angular.dart,giovannicandido/angular.dart,rkirov/angular.dart,ronlobo/angular.dart,hitesh97/angular.dart,trinarytree/angular.dart,rkirov/angular.dart,rkirov/angular.dart,trinarytree/angular.dart,giovannicandido/angular.dart,ronlobo/angular.dart,hitesh97/angular.dart,trinarytree/angular.dart,giovannicandido/angular.dart,ronlobo/angular.dart,SibuStephen/angular.dart,winstonewert/angular.dart