Update pip to 20.2.1

[pyup-bot]

This PR updates pip from 20.2 to 20.2.1.

Changelog

20.2.1

===================

Features
--------

- Ignore require-virtualenv in ``pip list`` (`8603 <https://github.com/pypa/pip/issues/8603>`_)

Bug Fixes
---------

- Correctly find already-installed distributions with dot (``.``) in the name
and uninstall them when needed. (`8645 <https://github.com/pypa/pip/issues/8645>`_)
- Trace a better error message on installation failure due to invalid ``.data``
files in wheels. (`8654 <https://github.com/pypa/pip/issues/8654>`_)
- Fix SVN version detection for alternative SVN distributions. (`8665 <https://github.com/pypa/pip/issues/8665>`_)
- New resolver: Correctly include the base package when specified with extras
in ``--no-deps`` mode. (`8677 <https://github.com/pypa/pip/issues/8677>`_)
- Use UTF-8 to handle ZIP archive entries on Python 2 according to PEP 427, so
non-ASCII paths can be resolved as expected. (`8684 <https://github.com/pypa/pip/issues/8684>`_)

Improved Documentation
----------------------

- Add details on old resolver deprecation and removal to migration documentation. (`8371 <https://github.com/pypa/pip/issues/8371>`_)
- Fix feature flag name in docs. (`8660 <https://github.com/pypa/pip/issues/8660>`_)

Links

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