test_packageindex.test_percent_in_password failing on Windows

[jaraco]

After adding support for Windows on Azure Pipelines in 6463fee, the tests started failing.

___________________ TestPyPIConfig.test_percent_in_password ___________________

self = <setuptools.tests.test_packageindex.TestPyPIConfig object at 0x0000025DA93BBFA0>
tmpdir = local('C:\\Users\\VssAdministrator\\AppData\\Local\\Temp\\pytest-of-unknown\\pytest-0\\test_percent_in_password0')
monkeypatch = <_pytest.monkeypatch.MonkeyPatch object at 0x0000025DAB1E8850>

    def test_percent_in_password(self, tmpdir, monkeypatch):
        monkeypatch.setitem(os.environ, 'HOME', str(tmpdir))
        pypirc = tmpdir / '.pypirc'
        pypirc.write(DALS("""
            [pypi]
            repository=https://pypi.org
            username=jaraco
            password=pity%
        """))
        print(os.path.expanduser('~'))
        print(str(tmpdir))
        cfg = setuptools.package_index.PyPIConfig()
>       cred = cfg.creds_by_repository['https://pypi.org']
E       KeyError: 'https://pypi.org'

setuptools\tests\test_packageindex.py:299: KeyError

I traced the issue to bpo-36264 where it seems that Python removed support for overriding the home directory on Windows through the HOME variable, now requiring a separate variable.