新版cocoapod 下载，报CDN、 port 443

[!] CDN: trunk Repo update failed - 23 error(s):
CDN: trunk URL couldn't be downloaded: https://raw.githubusercontent.com/CocoaPods/Specs/master/Specs/a/a/4/Masonry/0.0.2/Masonry.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：在Podfile文件中添加
  source "https://github.com/CocoaPods/Specs.git"

• 亲测有效，我的cocoapod版本1.8.4
  MacBook-Pro:~ silence$ pod --version
  1.8.4