1、根据域名查找IP:
https://github.com.ipaddress.com/
2、修改Hosts 如下：
140.82.114.9 codeload.github.com
140.82.114.3 github.com
140.82.113.3 gist.github.com
199.232.69.194 github.global.ssl.fastly.net
185.199.110.153 assets-cdn.github.com
199.232.68.133 raw.githubusercontent.com
199.232.68.133 cloud.githubusercontent.com
199.232.68.133 camo.githubusercontent.com
199.232.68.133 avatars0.githubusercontent.com
199.232.68.133 avatars1.githubusercontent.com
199.232.68.133 avatars2.githubusercontent.com
199.232.68.133 avatars3.githubusercontent.com
199.232.68.133 avatars4.githubusercontent.com
199.232.68.133 avatars5.githubusercontent.com
199.232.68.133 avatars6.githubusercontent.com
199.232.68.133 avatars7.githubusercontent.com
199.232.68.133 avatars8.githubusercontent.com
3、命令行刷新DNS：
ipconfig /flushdns
参考：