Update pip to 20.2.1

[pyup-bot]

This PR updates pip from 20.1.1 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>`_)

20.2

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

Deprecations and Removals
-------------------------

- Deprecate setup.py-based builds that do not generate an ``.egg-info`` directory. (`6998 <https://github.com/pypa/pip/issues/6998>`_, `8617 <https://github.com/pypa/pip/issues/8617>`_)
- Disallow passing install-location-related arguments in ``--install-options``. (`7309 <https://github.com/pypa/pip/issues/7309>`_)
- Add deprecation warning for invalid requirements format "base>=1.0[extra]" (`8288 <https://github.com/pypa/pip/issues/8288>`_)
- Deprecate legacy setup.py install when building a wheel failed for source
distributions without pyproject.toml (`8368 <https://github.com/pypa/pip/issues/8368>`_)
- Deprecate -b/--build/--build-dir/--build-directory. Its current behaviour is confusing
and breaks in case different versions of the same distribution need to be built during
the resolution process. Using the TMPDIR/TEMP/TMP environment variable, possibly
combined with --no-clean covers known use cases. (`8372 <https://github.com/pypa/pip/issues/8372>`_)
- Remove undocumented and deprecated option ``--always-unzip`` (`8408 <https://github.com/pypa/pip/issues/8408>`_)

Features
--------

- Log debugging information about pip, in ``pip install --verbose``. (`3166 <https://github.com/pypa/pip/issues/3166>`_)
- Refine error messages to avoid showing Python tracebacks when an HTTP error occurs. (`5380 <https://github.com/pypa/pip/issues/5380>`_)
- Install wheel files directly instead of extracting them to a temp directory. (`6030 <https://github.com/pypa/pip/issues/6030>`_)
- Add a beta version of pip's next-generation dependency resolver.

Move pip's new resolver into beta, remove the
``--unstable-feature=resolver`` flag, and enable the
``--use-feature=2020-resolver`` flag. The new resolver is
significantly stricter and more consistent when it receives
incompatible instructions, and reduces support for certain kinds of
:ref:`Constraints Files`, so some workarounds and workflows may
break. More details about how to test and migrate, and how to report
issues, at :ref:`Resolver changes 2020` . Maintainers are preparing to

20.2b1

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

Bug Fixes
---------

- Correctly treat wheels containing non-ASCII file contents so they can be
installed on Windows. (`5712 <https://github.com/pypa/pip/issues/5712>`_)
- Prompt the user for password if the keyring backend doesn't return one (`7998 <https://github.com/pypa/pip/issues/7998>`_)

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

- Add GitHub issue template for reporting when the dependency resolver fails (`8207 <https://github.com/pypa/pip/issues/8207>`_)

Links

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