Remove lock version for Rake

Author: AlexWayfer

grape-swagger-representable.gemspec

@@ -28,7 +28,7 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'pry-byebug' unless RUBY_PLATFORM.eql?('java') || RUBY_ENGINE.eql?('rbx')
   s.add_development_dependency 'rack-cors'
   s.add_development_dependency 'rack-test'
-  s.add_development_dependency 'rake', '~> 10.0'
+  s.add_development_dependency 'rake'
   s.add_development_dependency 'redcarpet' unless RUBY_PLATFORM.eql?('java') || RUBY_ENGINE.eql?('rbx')
   s.add_development_dependency 'rouge' unless RUBY_PLATFORM.eql?('java') || RUBY_ENGINE.eql?('rbx')
   s.add_development_dependency 'rspec', '~> 3.0'