Add Symfony 8 support

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Hello,

Would it be possible to create a new release that includes Symfony 8 support ?

Problem 1
    - Root composer.json requires phpro/grumphp * -> satisfiable by phpro/grumphp[v0.1.0, ..., v0.22.0, v1.0.0, ..., v1.16.0, v2.0.0, ..., v2.18.0].
    - gitonomy/gitlib[v1.3.0, ..., v1.3.8] require symfony/process ^3.4 || ^4.4 || ^5.0 || ^6.0 -> found symfony/process[v3.4.0, ..., v3.4.47, v4.4.0, ..., v4.4.44, v5.0.0, ..., v5.4.47, v6.0.0, ..., v6.4.31] but these were not loaded, likely because it conflicts with another require.
    - gitonomy/gitlib[v1.4.0, ..., v1.5.0] require symfony/process ^5.4 || ^6.0 || ^7.0 -> found symfony/process[v5.4.0, ..., v5.4.47, v6.0.0, ..., v6.4.31, v7.0.0, ..., v7.4.3] but these were not loaded, likely because it conflicts with another require.

I noticed that Symfony 8 support has already been added to the main branch in composer.json with symfony/process: ^5.4 || ^6.0 || ^7.0 || ^8.0, but there hasn't been a tagged release yet that includes this change.

Would you be able to tag a new release so that projects using Symfony 8 can benefit from this update?

Thank you very much for your time and for maintaining this library!