* Upgrade Symfony dependencies - allow the 5.x series of the Symfony components * Travis CI configuration and phpunit - update php versions to a today's usual choice - upgrade phpunit from 5.7 to 7.5, which was used from travis ci anyways * Fix setUp declaration - fix setUp() declaration to be compatible with PHPUnit\Framework\TestCase::setUp() * Fix setUp declaration - add :void to setUp() Co-authored-by: Sebastian Zipp <[email protected]>