[Gemspec] Update to unreleased cocoapods-plugins

This feels so wrong.

cocoapods.gemspec

@@ -31,7 +31,7 @@ Gem::Specification.new do |s|
   s.add_runtime_dependency 'claide',               '~> 0.7.0'
   s.add_runtime_dependency 'xcodeproj',            '~> 0.18.0'
   s.add_runtime_dependency 'cocoapods-downloader', '~> 0.6.1'
-  s.add_runtime_dependency 'cocoapods-plugins',    '~> 0.2.0'
+  s.add_runtime_dependency 'cocoapods-plugins',    '~> 0.3.0'
   s.add_runtime_dependency 'cocoapods-try',        '~> 0.3.0'
   s.add_runtime_dependency 'cocoapods-trunk',      '~> 0.1.4'