twine check should catch quotes in URLs

[henryiii]

Currently, twine check doesn't catch this in a setup.cfg file:

url = "https://github.com/pybind/pybind11"

which creates this in pybind11-2.6.0b1.dist-info/METADATA:

Home-page: "https://github.com/pybind/pybind11"

which fails to upload to PyPI.

HTTPError: 400 Bad Request from https://upload.pypi.org/legacy/
24
'"https://github.com/pybind/pybind11"' is an invalid value for Home-Page. Error: Invalid URI See https://packaging.python.org/specifications/core-metadata for more information.

[sigmavirus24]

Yeah, that makes sense. It's not terribly hard to do either.

[bhrutledge]

This feels like a duplicate of #430, along with #589, which is currently blocked by pypa/packaging#147.

I've started keeping track of all of these related issues in https://github.com/pypa/twine/projects/2.