Bump rake version

Author: jenseng

Gemfile

@@ -10,6 +10,6 @@ group :development do
 end
 
 group :test do
-  gem 'rake', '~> 10.0'
+  gem 'rake', '~> 12.3.3'
   gem 'rspec', '~> 2.14.0'
 end