See a list of composer configuration settings.
composer config --list -g
Check to see if you already set a github personal access token
composer config --list -g | grep github-oauth.github.com
Set your github personal access token
composer config --global github-oauth.github.com TOKEN
Disabling xdebug so composer goes quicker but setting php aliases so it still enabled
compsoer docs
Other options for setting the personal access token
http://www.gamez.name/avoid-github-rate-limits-when-using-composer/
The composer CLI docs
https://getcomposer.org/doc/03-cli.md