Update virtualenv to 20.1.0

[pyup-bot]

This PR updates virtualenv from 20.0.33 to 20.1.0.

Changelog

20.0.35

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- Bump embedded setuptools from ``50.3.0`` to ``50.3.1`` - by :user:`gaborbernat`. (`1982 <https://github.com/pypa/virtualenv/issues/1982>`_)
- After importing virtualenv passing cwd to a subprocess calls breaks with ``invalid directory`` - by :user:`gaborbernat`. (`1983 <https://github.com/pypa/virtualenv/issues/1983>`_)

20.0.34

~~~~~~~~~~~~~~~~~~
- Align with venv module when creating virtual environments with builtin creator on Windows 3.7 and later
- by :user:`gaborbernat`. (`1782 <https://github.com/pypa/virtualenv/issues/1782>`_)
- Handle Cygwin path conversion in the activation script - by :user:`davidcoghlan`. (`1969 <https://github.com/pypa/virtualenv/issues/1969>`_)

Links

• PyPI: https://pypi.org/project/virtualenv
• Changelog: https://pyup.io/changelogs/virtualenv/
• Homepage: https://virtualenv.pypa.io/