generate StrEnum for python 3.11+

[jochs]

(str, Enum) mixins have undergone a breaking change in python 3.11 - see https://github.com/python/cpython/issues/100458

This PR adds poetry core to the dependencies to allow for version constraint parsing, and lists an explicit set of python minor versions to allow.

The target version is the lowest version that satisfies the constraint.

Also I don't have a good way to generate the lockfiles with poetry 1.7, so if somebody could regenerate them for me that'd be appreciated