Support Symfony 8

[whataboutpereira]

I briefly looked at getting it work on Symfony 8 starting from tests, but I see there have been incompatible changes between v7 and v8 like XmlFileLoader not existing any more.

1) Shivas\VersioningBundle\Tests\BundleInitializationTest::testInitBundle
Error: Class "Symfony\Component\DependencyInjection\Loader\XmlFileLoader" not found

[Supportic]

Created PR to fix this: #100