Allow any python in the 3.x series >=3.7

[mmv]

Before converting from setup.py to pyproject, this upper bound didn't exist.

There's no reason to cap at 3.10. This breaks installations on other poetry projects defined with Python=^3.7 and would force updating this file for every new python version.

[dbrattli]

Instead of this I suggest that you change python-package.yaml to test specifically for a higher python version e.g 3.11.0-beta.4 so we know if it actually works or not. See https://github.com/actions/python-versions. Then we can change pyproject.toml to also include 3.11.

[dbrattli]

This makes me unsure if we should accept every new minor version: https://stackoverflow.com/questions/60421663/is-python-3-semantically-versioned-and-forwards-compatible. But I understand the frustration of not being able to use it if it actually works. Parts of me want to approve this PR 😄

[coveralls]

Coverage remained the same at 93.375% when pulling 696fbc6 on mmv:patch-1 into 4d351c9 on ReactiveX:master.

[dbrattli]

Thanks for fixing

[MainRo]

Thanks @dbrattli ! I also felt this restriction was... too restrictive.