Properly case project name from pypi.org.

def proper_case(package_name):
    """Properly case project name from pypi.org."""
    # Hit the simple API.
    r = _get_requests_session().get(
        "https://pypi.org/pypi/{0}/json".format(package_name), timeout=0.3, stream=True
    )
    if not r.ok:
        raise IOError(
            "Unable to find package {0} in PyPI repository.".format(package_name)
        )

    r = parse.parse("https://pypi.org/pypi/{name}/json", r.url)
    good_name = r["name"]
    return good_name