Update pubspec.yaml to 0.6.0 (dart-lang/gcloud#56)

diff --git a/pkgs/gcloud/pubspec.yaml b/pkgs/gcloud/pubspec.yaml
index 9f4432b..2f0cd16 100644
--- a/pkgs/gcloud/pubspec.yaml
+++ b/pkgs/gcloud/pubspec.yaml
@@ -1,5 +1,5 @@
 name: gcloud
-version: 0.5.0
+version: 0.6.0
 author: Dart Team <misc@dartlang.org>
 description: Dart gcloud APIs
 homepage: https://github.com/dart-lang/gcloud