Build with parallel composer downloads on Travis
Build with parallel composer downloads on Travis

Done by the composer hirak/prestissimo plugin.

A quick review on Travis for Magerun 2 shows timings from reduced from
270s down to 98s for the "before_script" part which's largest part is the
Magento installation that is done via composer.

Refs:

- https://github.com/hirak/prestissimo

pocallaghan/n98-magerun,tkn98/n98-magerun,tkn98/n98-magerun,tkn98/n98-magerun,pocallaghan/n98-magerun,pocallaghan/n98-magerun