Update composer dependencies

[jmleroux]

• PagerFanta is not a dev-only requirement. It is used in Model\Project
• Upgraded PHP Unit to a more recent version and modified the tests accordingly
• Fixed the Sylius resource component (@dev is a bit dangerous ;) )
• Use PHP CS Fixer on Travis CI

[jmleroux]

Hello, Do not hesitate to post any feedback on this PR for me to know if it is relevant.

[jmleroux]

Hello, Thank you for approving this PR. Do I have something else to do to have this PR merged?