windows：
Windows电脑有时打不开GitHub，修改host文件即可
https://www.jianshu.com/p/3eacebfc55ab
https://www.cnblogs.com/Java-Script/p/11090777.html
host文件修改方法：
找到host文件路径：
C:\WINDOWS\System32\drivers\etc
在最后添加host
#github
192.30.253.112 github.com
151.101.113.194 github.global.SSL.fastly.net
dns刷新，打开cmd：
ipconfig /flushdns
注：
192.30.253.112是查找的github的网址
151.101.113.194是查找github.global.ssl.fastly.net网址
另外一种方式
1.打开Dns检测|Dns查询 - 站长工具
2.在检测输入栏中输入http://github.com官网
3.把检测列表里的TTL值最小的IP输入到hosts里，并对应写上github官网域名
https://github.com.ipaddress.com
Mac ：
host路径
/private/etc
添加网址到 host
# GitHub Start
192.30.253.112 Build software better, together
192.30.253.119 gist.github.com
151.101.184.133 assets-cdn.github.com
151.101.184.133 raw.githubusercontent.com
151.101.184.133 gist.githubusercontent.com
151.101.184.133 cloud.githubusercontent.com
151.101.184.133 camo.githubusercontent.com
151.101.184.133 avatars0.githubusercontent.com
151.101.184.133 avatars1.githubusercontent.com
151.101.184.133 avatars2.githubusercontent.com
151.101.184.133 avatars3.githubusercontent.com
151.101.184.133 avatars4.githubusercontent.com
151.101.184.133 avatars5.githubusercontent.com
151.101.184.133 avatars6.githubusercontent.com
151.101.184.133 avatars7.githubusercontent.com
151.101.184.133 avatars8.githubusercontent.com
199.232.96.133 user-images.githubusercontent.com
# GitHub End
