1.切换gem源
gem sources --remove https://rubygems.org/
gem source -a http://gems.ruby-china.com
2.查看是否成功
gem source -l
打印出*** CURRENT SOURCES ***
http://gems.ruby-china.com
3.升级
sudo gem install -n /usr/local/bin cocoapods --pre
4.检查版本
pod --version
5.设置仓库
pod setup