$ sudo -u _www php composer.phar update
Loading composer repositories with package information
Updating dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - Installation request for moodlehq/behat-extension 3.400.2 -> satisfiable by moodlehq/behat-extension[v3.400.2].
    - moodlehq/behat-extension v3.400.2 requires oleg-andreyev/mink-facebook-web-driver dev-w3c -> no matching package found.