1.安装最新ruby镜像 gem sources --add https://gems.ruby-china.org/ 报错
报错信息：Error fetching https://gems.ruby-china.org/:
bad response Not Found 404 (https://gems.ruby-china.org/specs.4.8.gz)
解决方法：由于域名变更，导致 https://gems.ruby-china.org/ 无法响应，将.org 改成.com 就可以了
2.更新版本 sudo gem install cocoapods 报错
报错信息：While executing gem ... (Gem::FilePermissionError)
You don't have write permissions for the /usr/bin directory.
解决方法：改为 sudo gem install -n /usr/local/bin cocoapods 即可
