“клонировать Dev Masters of the Package git” Ответ

клонировать Dev Masters of the Package git

Inside you composer.json add the following code

"require": { "behat/mink-selenium2-driver" : "dev-master" }
"minimum-stability": "dev"

################ OR ########################

Simply using the composer command : 

composer require --dev behat/mink-selenium2-driver:dev-master