CS-fixer is a dependency of build-parallel
Merge branch 'hotfix/4284'

Close #4293
Fixes #4284 properly
No need to `cd` to the php-cs-fixer dir
Merge pull request #4321 from Ocramius/hotfix/cs-fixer-installation

Hotfix/cs fixer installation
Merge branch 'hotfix/4321' into develop

Forward port #4321