[gemspec] Bump Xcodeproj to `~> 0.21.1`

Gemfile.lock

@@ -24,10 +24,10 @@ GIT
 
 GIT
   remote: https://github.com/CocoaPods/Xcodeproj.git
-  revision: 2ef226943bf432aef0b610fcbe8b99e9ae9ef1f8
+  revision: 55a78cee57530d8b831f0926dd5c3084c47b7c4d
   branch: master
   specs:
-    xcodeproj (0.21.0)
+    xcodeproj (0.21.1)
       activesupport (>= 3)
       colored (~> 1.2)
 
@@ -78,7 +78,7 @@ PATH
       molinillo (~> 0.2.0)
       nap (~> 0.8)
       open4 (~> 1.3)
-      xcodeproj (~> 0.21.0)
+      xcodeproj (~> 0.21.1)
 
 GEM
   remote: http://rubygems.org/
@@ -118,7 +118,7 @@ GEM
       rb-kqueue (>= 0.2)
     metaclass (0.0.4)
     method_source (0.8.2)
-    minitest (5.5.0)
+    minitest (5.5.1)
     mocha (1.1.0)
       metaclass (~> 0.0.1)
     mocha-on-bacon (0.2.2)

cocoapods.gemspec

@@ -29,7 +29,7 @@ Gem::Specification.new do |s|
   # Link with the version of CocoaPods-Core
   s.add_runtime_dependency 'cocoapods-core',       "= #{Pod::VERSION}"
   s.add_runtime_dependency 'claide',               '~> 0.8.0'
-  s.add_runtime_dependency 'xcodeproj',            '~> 0.21.0'
+  s.add_runtime_dependency 'xcodeproj',            '~> 0.21.1'
   s.add_runtime_dependency 'cocoapods-downloader', '~> 0.8.1'
   s.add_runtime_dependency 'cocoapods-plugins',    '~> 0.4.0'
   s.add_runtime_dependency 'cocoapods-try',        '~> 0.4.3'