尝试使用Cocoapods通过pod install命令安装pod时出现此错误。我刚刚更新到Cocoapods 0.33.1，我不知道是否是造成这种情况的原因。
我查看了Cocoapods Github回购，但似乎没有类似的问题。
### Stack
```
CocoaPods : 0.33.1
Ruby : ruby 2.0.0p451 (2014-02-24 revision 45167) [universal.x86_64-darwin13]
RubyGems : 2.0.14
Host : Mac OS X 10.9.3 (13D65)
Xcode : 5.1.1 (5B1008)
Ruby lib dir : /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib
Repositories : master - https://github.com/CocoaPods/Specs.git @ a9178ca54fa395859f71056e7015fd125fa93495
```
### Podfile
```ruby
platform :ios, '7.0'
pod 'OpenWeatherMapAPI', '~> 0.0.5'
```
### Error
```
RuntimeError - [!] Xcodeproj doesn't know about the following attributes {"name"=>"JSON"} for the 'PBXReferenceProxy' isa.
Please file an issue: https://github.com/CocoaPods/Xcodeproj/issues/new
/Library/Ruby/Gems/2.0.0/gems/xcodeproj-0.17.0/lib/xcodeproj/project/object.rb:300:in `configure_with_plist'
/Library/Ruby/Gems/2.0.0/gems/xcodeproj-0.17.0/lib/xcodeproj/project.rb:230:in `new_from_plist'
/Library/Ruby/Gems/2.0.0/gems/xcodeproj-0.17.0/lib/xcodeproj/project/object.rb:328:in `object_with_uuid'
/Library/Ruby/Gems/2.0.0/gems/xcodeproj-0.17.0/lib/xcodeproj/project/object.rb:279:in `block (2 levels) in configure_with_plist'
/Library/Ruby/Gems/2.0.0/gems/xcodeproj-0.17.0/lib/xcodeproj/project/object.rb:278:in `each'
/Library/Ruby/Gems/2.0.0/gems/xcodeproj-0.17.0/lib/xcodeproj/project/object.rb:278:in `block in configure_with_plist'
/Library/Ruby/Gems/2.0.0/gems/xcodeproj-0.17.0/lib/xcodeproj/project/object.rb:275:in `each'
/Library/Ruby/Gems/2.0.0/gems/xcodeproj-0.17.0/lib/xcodeproj/project/object.rb:275:in `configure_with_plist'
/Library/Ruby/Gems/2.0.0/gems/xcodeproj-0.17.0/lib/xcodeproj/project.rb:230:in `new_from_plist'
/Library/Ruby/Gems/2.0.0/gems/xcodeproj-0.17.0/lib/xcodeproj/project/object.rb:328:in `object_with_uuid'
/Library/Ruby/Gems/2.0.0/gems/xcodeproj-0.17.0/lib/xcodeproj/project/object.rb:291:in `block (3 levels) in configure_with_plist'
/Library/Ruby/Gems/2.0.0/gems/xcodeproj-0.17.0/lib/xcodeproj/project/object.rb:290:in `each'
/Library/Ruby/Gems/2.0.0/gems/xcodeproj-0.17.0/lib/xcodeproj/project/object.rb:290:in `block (2 levels) in configure_with_plist'
/Library/Ruby/Gems/2.0.0/gems/xcodeproj-0.17.0/lib/xcodeproj/project/object.rb:288:in `each'
/Library/Ruby/Gems/2.0.0/gems/xcodeproj-0.17.0/lib/xcodeproj/project/object.rb:288:in `block in configure_with_plist'
/Library/Ruby/Gems/2.0.0/gems/xcodeproj-0.17.0/lib/xcodeproj/project/object.rb:285:in `each'
/Library/Ruby/Gems/2.0.0/gems/xcodeproj-0.17.0/lib/xcodeproj/project/object.rb:285:in `configure_with_plist'
/Library/Ruby/Gems/2.0.0/gems/xcodeproj-0.17.0/lib/xcodeproj/project.rb:230:in `new_from_plist'
/Library/Ruby/Gems/2.0.0/gems/xcodeproj-0.17.0/lib/xcodeproj/project.rb:175:in `initialize_from_file'
/Library/Ruby/Gems/2.0.0/gems/xcodeproj-0.17.0/lib/xcodeproj/project.rb:93:in `open'
/Library/Ruby/Gems/2.0.0/gems/cocoapods-0.33.1/lib/cocoapods/installer/analyzer.rb:517:in `block in compute_target_platforms'
/Library/Ruby/Gems/2.0.0/gems/cocoapods-0.33.1/lib/cocoapods/installer/analyzer.rb:514:in `each'
/Library/Ruby/Gems/2.0.0/gems/cocoapods-0.33.1/lib/cocoapods/installer/analyzer.rb:514:in `compute_target_platforms'
/Library/Ruby/Gems/2.0.0/gems/cocoapods-0.33.1/lib/cocoapods/installer/analyzer.rb:55:in `analyze'
/Library/Ruby/Gems/2.0.0/gems/cocoapods-0.33.1/lib/cocoapods/installer.rb:176:in `analyze'
/Library/Ruby/Gems/2.0.0/gems/cocoapods-0.33.1/lib/cocoapods/installer.rb:98:in `block in resolve_dependencies'
/Library/Ruby/Gems/2.0.0/gems/cocoapods-0.33.1/lib/cocoapods/user_interface.rb:52:in `section'
/Library/Ruby/Gems/2.0.0/gems/cocoapods-0.33.1/lib/cocoapods/installer.rb:97:in `resolve_dependencies'
/Library/Ruby/Gems/2.0.0/gems/cocoapods-0.33.1/lib/cocoapods/installer.rb:89:in `install!'
/Library/Ruby/Gems/2.0.0/gems/cocoapods-0.33.1/lib/cocoapods/command/project.rb:40:in `run_install_with_update'
/Library/Ruby/Gems/2.0.0/gems/cocoapods-0.33.1/lib/cocoapods/command/project.rb:70:in `run'
/Library/Ruby/Gems/2.0.0/gems/claide-0.6.1/lib/claide/command.rb:281:in `run'
/Library/Ruby/Gems/2.0.0/gems/cocoapods-0.33.1/lib/cocoapods/command.rb:48:in `run'
/Library/Ruby/Gems/2.0.0/gems/cocoapods-0.33.1/bin/pod:33:in `<top (required)>'
/usr/bin/pod:23:in `load'
/usr/bin/pod:23:in `<main>'
```
我该怎么办？ 谢谢你的帮助！