Deprecated extension

[garak]

In Symfony 7.1:

The "Symfony\Component\HttpKernel\DependencyInjection\Extension" class is considered internal since Symfony 7.1, to be deprecated in 8.1; use Symfony\Component\DependencyInjection\Extension\Extension instead. It may change without further notice. You should not use it from "Beelab\Recaptcha2Bundle\DependencyInjection\BeelabRecaptcha2Extension".

In Symfony 6.4 the proper class is already present, so we should extend for it to guarantee maximum forward compatibility.