Bump the barback minor version.

This will ensure that next week's dev channel release will force
everyone to use compatible pub and barback versions.

R=rnystrom@google.com
BUG=

Review URL: https://codereview.chromium.org//99303005

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@31001 260f80e4-7a28-3924-810f-c04153c831b5

lib/src/barback.dart

@@ -40,7 +40,7 @@ export 'barback/sources.dart' show WatcherType;
 ///
 /// Whenever a new non-patch version of barback is published, this *must* be
 /// incremented to synchronize with that.
-final supportedVersion = new Version(0, 10, 0);
+final supportedVersion = new Version(0, 11, 0);
 
 /// An identifier for a transformer and the configuration that will be passed to
 /// it.