Add support for symfony/yaml version ^7

[ovidiuenache]

There have been some talks about removing this dependency from the list of required packages and there is an issue created regarding this (#170). However, there has been no update on it and I believe we should either remove it or keep it updated. This issue is focusing on the latter.

I'll open a PR about this.

[ovidiuenache]

#202

[ovidiuenache]

cc @cebe

[tacman]

Hi @cebe thanks for putting this library together. Any chance you could approve allowing the Symfony 7 YAML parser?

If you are going to release a new version, you could even just support php 8.1+ and Symfony 6/7.