更新cocoapods出现的坑

$ sudo gem update --system // 先更新gem，国内需要切换源

$ gem sources --remove https://rubygems.org/

$ gem sources -a https://ruby.taobao.org/

$ gem sources -l

\*\*\* CURRENT SOURCES \*\*\*

https://ruby.taobao.org/

$ sudo gem install -n /usr/local/bin cocoapods --pre// 安装cocoapods

$ pod setup