[gemspec] Update cocoapods-trunk to `~> 0.6.0`

cocoapods.gemspec

@@ -33,7 +33,7 @@ Gem::Specification.new do |s|
   s.add_runtime_dependency 'cocoapods-downloader', '~> 0.8.1'
   s.add_runtime_dependency 'cocoapods-plugins',    '~> 0.4.1'
   s.add_runtime_dependency 'cocoapods-try',        '~> 0.4.3'
-  s.add_runtime_dependency 'cocoapods-trunk',      '~> 0.5.1'
+  s.add_runtime_dependency 'cocoapods-trunk',      '~> 0.6.0'
   s.add_runtime_dependency 'molinillo',            '~> 0.2.1'
 
   s.add_runtime_dependency 'colored',       '~> 1.2'