Rev packages again and this time update the mojo_sdk dependency

sky/packages/sky_engine/pubspec.yaml

 name: sky_engine
-version: 0.0.54
+version: 0.0.55
 author: Flutter Authors <flutter-dev@googlegroups.com>
 description: Dart SDK extensions for dart:ui
 homepage: http://flutter.io

sky/packages/sky_services/pubspec.yaml

 name: sky_services
-version: 0.0.54
+version: 0.0.55
 author: Flutter Authors <flutter-dev@googlegroups.com>
 description: Mojom interfaces associated with Flutter
 homepage: http://flutter.io
 dependencies:
-  mojo_sdk: 0.2.1
+  mojo_sdk: 0.2.2
 environment:
   sdk: '>=1.8.0 <2.0.0'