Stop passing author.email to python

[evandrocoan]

I have this project I am setting up on PYPI (ankitects/anki#535 (comment)), but it is not working right because the project has no email.
F:\anki>twine upload "dist\ankirspy2-2.1.31-cp38-none-win_amd64.whl" Uploading ankirspy2-2.1.31-cp38-none-win_amd64.whl ███████████████████████████████████████████| 3.00M/3.00M [00:10<00:00, 291kB/s] NOTE: Try --verbose to see response content. HTTPError: 400 Client Error: 'Ankitects Pty Ltd and contributors' is an invalid value for Author-email. Error: Use a valid email address See https://packaging.python.org/specifications/core-metadata for url: https://upload.pypi.org/legacy/

maturin should detect there is no email in the authors tag and not generate the wheel with author.email flags. Other pythons wheels (from setup.py) on that project work fine with pypi and do not use author.email thing: https://github.com/ankitects/anki/blob/6cf3b0ca18b7544f127f3563b2e4ddb71253efa9/pylib/setup.py#L19

setuptools.setup(
    name="anki",
    version="2.1.24",  # automatically updated
    author="Ankitects Pty Ltd", <----------------------------