feature request: support Enum by Value

[sanzoghenzo]

Hi there!

First of all, kudos for your great work!

I started to use this library, and my data structure serializes the enums using their values instead of the name.

Are you willing to accept a PR to allow the parsing of the enum both by name or value?

[Zaharid]

I have added a feature to define custom parsers, documented here

https://validobj.readthedocs.io/en/latest/custom.html

It should allow to more or less easily implement this kind of logic externally.

[sanzoghenzo]

Thanks, I will try that ASAP.

This is also handy for numpy arrays and pydantic models!