Convert to pyproject.toml and publish on pypi on new tag (closes #42)

[tfmoraes]

This PR converts from setup.py to pyproject.toml. Also uses Github CI to publish on Pypi. It uses https://github.com/pypa/gh-action-pypi-publish to publish. You'll need to create a new user on Pypi. Create a new Token API and add this token to this repo as a secrete with the name PYPI_API_TOKEN (because that is the name used on the ci file). You also need to do this https://docs.pypi.org/trusted-publishers/ and the name of publishing workflow is publish-pypi.yaml. Very probably you will need to create a new project with other name, because already exists a sdf. Also the project name on pyproject.toml must be changed to match the pypi project name.

[nobodyinperson]

Good work but this project has been pretty dead and unresponsive for a long time. I forked it to sdfcad https://gitlab.com/nobodyinperson/sdfcad and also put it on PyPI with poetry and a load of other fixes and features.

[tfmoraes]

@nobodyinperson thanks for the info. Good to know about sfdcad it will be very useful to me. I'll leave this PR open if @fogleman wants to merge it.