cocoapods问题

1. CDN: trunk URL couldn't be downloaded: https://raw.githubusercontent.com/CocoaPods/Specs/master/Specs/1/f/6/SnapKit/5.0.1/SnapKit.podspec.json, error: Failed to open TCP connection to raw.githubusercontent.com:443 (Connection refused - connect(2) for "raw.githubusercontent.com" port 443)

解决方法:
按照官方文档 podfile文件中添加source源：
source 'https://github.com/CocoaPods/Specs.git'

详解见: https://www.jianshu.com/p/bf1cbe49cb5d