Support Symfony 7

[tacman]

The library is currently limited to Symfony 5 and 6.

IF you were going to be releasing a new version, I would suggest dropping PHP 7 and only supporting Symfony ^6.3 || ^7.0

[tacman]

Oops, I added another PR without checking. @allansun , can you approve one of the PRs so that the library will at least install with Symfony 7? It's only yaml and property-info.

Thx.