Request: Add Python package: pipx

[Ross Patterson]

Please add a `python3-pipx` package to the central Cygwin package repo/index.

Running `# pip3 install ...` in Debian-based distributions now fails
with a warning about breaking the system Python installation and that
warning message, following the PyPA itself, blesses `# pipx install
--global` as the way to install python packages system-wide (or on the
user's PATH) without breaking the system python installation or other
locally installed Python packages. It, much like `$ tox`, is a
meta-python tool that many users will find useful, if not depend on,
that must be installed globally/per-user and not per-project.

Thank you for your consideration,
Ross