$ flutter upgrade

Flutter 0.5.1 • channel beta • https://github.com/flutter/flutter.git
Framework • revision c7ea3ca377 (9 weeks ago) • 2018-05-29 21:07:33 +0200
Engine • revision 1ed25ca7b7
Tools • Dart 2.0.0-dev.58.0.flutter-f981f09760