pyproject.toml compatibility with future python

[anthraxx]

It would be great if this project can implement future pyproject.toml declaration requirement as otherwise future python versions won't be able to be used with this project. It's always good to be ready before the deadline hits :cat:

https://packaging.python.org/en/latest/guides/writing-pyproject-toml/

thanks! :)

[sashs]

Hey. Thank you. :) I will look at that as soon as I have fixed the pyvex issue.