CocoaPods bad response Not Found 404 (http://ruby.taobao.org/specs.4.8.gz)解决

CocoaPods 安装错误：
Error fetching http://ruby.taobao.org/:
bad response Not Found 404 (http://ruby.taobao.org/specs.4.8.gz)
解决方案：把安装流程中 $gem sources -a http://ruby.taobao.org/ ---改为---->$gem sources -a https://ruby.taobao.org/