cocoapods : pod install 报错

报错日志：

[!] Oh no, an error occurred.

Search for existing GitHub issues similar to yours:
https://github.com/CocoaPods/CocoaPods/search?q=%5BXcodeproj%5D+Unknown+object+version.&type=Issues

If none exists, create a ticket, with the template displayed above, on:
https://github.com/CocoaPods/CocoaPods/issues/new

Be sure to first read the contributing guide for details on how to properly submit a ticket:
https://github.com/CocoaPods/CocoaPods/blob/master/CONTRIBUTING.md

解决办法：

一、首先查看一下自己的ruby，看是不是 https://gems.ruby-china.com/

gem sources -l

二、如果不是 https://gems.ruby-china.com/ 的源的话，就添加新源，卸载旧源；

gem sources --add https://gems.ruby-china.com/ --remove https://gems.ruby-china.org/

三、再次查看自己的ruby，看是否替换成功。如果显示是https://gems.ruby-china.com/则说明替换成功。

gem sources -l

四、重新初始化安装Pod。

sudo gem install -n /usr/local/bin cocoapods

五、成功之后查看一下版本有无,现在最新的是 1.5.3 版本。

pod --version

六、如果没什么问题的话吗，就cd到自己的工程目录下进行更新第三方库

pod install --verbose --no-repo-update