Allow Symfony ^8.0 and use PHP configuration

[knallcharge]

No description provided.

[bytehead]

@knallcharge are you gonna fix the CS and adjust the requirements for the tests under PHP 8 and Symfony 6?

[knallcharge]

Code style has been fixed.
As I don't use pipelines, I'm not really familiar with those, but I excluded PHP 8 with Symfony 6.0 as it needs PHP 8.1 - if that's what you meant, you're good to go now.

[bytehead]

Thank you @knallcharge!