How would this feature be useful?

I think it would really spare some work to not have to hard-code the Python versions to use in nox's session decorator or elsewhere. Version specifiers are a clean and efficient way to specify version ranges and exclude versions. packaging could handle the parsing of the specifier set, as it's also already a dependency of nox. This might also be useful regarding what #811 proposes.

Describe the solution you'd like

Being able to specify something like the following in the end:

@nox.session(python=">=3.8,<=3.12,!=3.9")
def tests(session):
    pass

Describe alternatives you've considered

Working with the Python specification syntax that exists currently, which isn't too tedious.

Anything else?

No response