github链接不上的问题

1. 查找github的ip地址
   https://ping.chinaz.com/github.com
2. 修改host
   sudo vi /etc/hosts

##
# Host Database
#
# localhost is used to configure the loopback interface
# when the system is booting.  Do not change this entry.
##
127.0.0.1   localhost
255.255.255.255 broadcasthost
::1             localhost
185.199.111.133  raw.githubusercontent.com
20.205.243.166 github.com
#199.232.96.133  raw.github.com
#172.67.74.167  cdn.cocoapods.org

3. 刷新DNS缓存
   sudo killall -HUP mDNSResponder