Put these in your /etc/hosts file:

192.30.253.113  github.com
151.101.44.133  assets-cdn.github.com
54.236.140.90   collector.githubapp.com
192.30.253.116  api.github.com
192.30.253.122  ssh.github.com
151.101.44.133  avatars0.githubusercontent.com
151.101.44.133  avatars1.githubusercontent.com
151.101.44.133  avatars2.githubusercontent.com
151.101.44.133  avatars3.githubusercontent.com

Windows users:

Edit the file

    C:\Windows\System32\drivers\etc\hosts

You will need to be an administrator to change it - find notepad in start menu
under accessories, right mouse click on it and "run as administrator",
then load the file using file open.

Copied from:

    https://www.reddit.com/r/programming/comments/58o5p6/github_is_down/

This got gitub working again for me.