Update version of PHP CS Fixer

[intraordinaire]

Questions	Answers
Description?	Update CS-Fixer version to 3.x, fix deprecation related to that change
Type?	improvement
BC breaks?	yes
Deprecations?	no
Possible impacts?	If the init script is not launched or the config file is not renamed, the old config file will remained, and cs-fixer will probably do not work correctly until it's done.

[Progi1984]

Thanks @intraordinaire