Change GitHub Mapbox.js branch in Rakefile from 'v2' to current default branch, 'mb-pages'

Author: nbumbarger

Rakefile

@@ -5,7 +5,7 @@ require File.expand_path('../lib/mapbox-rails/remote_resource_loader', __FILE__)
 desc "Update with MapBox's Mapbox.js Library"
 task 'update-mapbox' do |task, args|
   remote = args['remote'] || 'https://github.com/mapbox/mapbox.js'
-  branch = args['branch'] || 'v2'
+  branch = args['branch'] || 'mb-pages'
   loader = RemoteResourceLoader.new
   loader.fetch
   loader.convert