Bump Xcodeproj dependency.

cocoapods.gemspec

@@ -30,7 +30,7 @@ Gem::Specification.new do |s|
   s.add_runtime_dependency 'cocoapods-core',       "= #{Pod::VERSION}"
   s.add_runtime_dependency 'claide',               '~> 0.1'
   s.add_runtime_dependency 'cocoapods-downloader', '~> 0.1'
-  s.add_runtime_dependency 'xcodeproj',            '~> 0.4.3'
+  s.add_runtime_dependency 'xcodeproj',            '~> 0.5.0'
 
   s.add_runtime_dependency 'faraday',       '~> 0.8.1'
   s.add_runtime_dependency 'octokit',       '~> 1.7'