Self-tests fail against pip 22.3

[stanislavlevin]

/usr/src/RPM/BUILD/python3-module-pytest-sugar-0.9.5$ /usr/src/RPM/BUILD/python3-module-pytest-sugar-0.9.5/.tox/py3/bin/python -m pip install --use-feature=2020-resolver --use-feature=fast-deps --exists-action w .tox/.tmp/package/1/pytest_sugar-0.9.5-py2.py3-none-any.whl

Usage:   
  /usr/src/RPM/BUILD/python3-module-pytest-sugar-0.9.5/.tox/py3/bin/python -m pip install [options] <requirement specifier> [package-index-options] ...
  /usr/src/RPM/BUILD/python3-module-pytest-sugar-0.9.5/.tox/py3/bin/python -m pip install [options] -r <requirements file> [package-index-options] ...
  /usr/src/RPM/BUILD/python3-module-pytest-sugar-0.9.5/.tox/py3/bin/python -m pip install [options] [-e] <vcs project url> ...
  /usr/src/RPM/BUILD/python3-module-pytest-sugar-0.9.5/.tox/py3/bin/python -m pip install [options] [-e] <local project path> ...
  /usr/src/RPM/BUILD/python3-module-pytest-sugar-0.9.5/.tox/py3/bin/python -m pip install [options] <archive url/path> ...

option --use-feature: invalid choice: '2020-resolver' (choose from 'fast-deps', 'truststore', 'no-binary-enable-wheel-cache')
ERROR: invocation failed (exit code 2)

https://pip.pypa.io/en/stable/news/#v22-3:

Remove --use-feature=2020-resolver opt-in flag. This was supposed to be removed in 21.0, but missed during that release cycle. (#11493)

[Teemu]

Fixed