Update pyproject.toml version on releases

[igorsobreira]

#75 (comment)

[rafaelcaricio]

In other projects that I've used similar approach (setting versions in the CI before publishing to PyPI). I used to have a fake version in the repo like 0.0.0 or 2020.0.dev. Something that is obviously not the version and follow https://www.python.org/dev/peps/pep-0440/

[rafaelcaricio]

For example, here https://github.com/zalando/connexion/blob/master/connexion/__init__.py#L48