Pod setup Pod update 错误fix

参考
https://www.jianshu.com/p/8c53d72b7ff8
https://www.jianshu.com/p/a977c0a03bf4
https://blog.csdn.net/smxalong/article/details/84402789

删除目录
sudo rm -fr ~/.cocoapods/repos/master

去下载zip包 或者 clone一份
推荐clone
git clone https://git.coding.net/CocoaPods/Specs.git  ~/.cocoapods/repos/master