[Installation] Setuptools deprecation: "Usage of dash-separated 'description-file' will not be supported in future versions. Please use the underscore name 'description_file' instead"

[leycec]

While packaging rshell for Gentoo Linux (:hugs:), I stumbled over two minor roadblocks in setup.py that you'll probably want to resolve sooner than later:

1. Setuptools deprecation warning: "Usage of dash-separated 'description-file' will not be supported in future versions. Please use the underscore name 'description_file' instead". So, rshell will cease to be installable sometime in 2022 or 2023. Thankfully, resolving this is trivial. Just rename the description-file key in your top-level setup.cfg file to description_file instead. Boom. Done.
2. Gentoo QA failure: "Package installs 'tests' package which is forbidden and likely a bug in the build system." Since tests is an ambiguous package name, no setup.py file should ever install that package. Doing so means that (A) you're almost certainly overwriting someone else's erroneously installed tests package and (B) your own erroneously installed tests package will be overwritten in turn by someone else. Thankfully, resolving this is trivial too. Just drop the ", 'tests'" substring from your top-level setup.py file: e.g.,

    # Do this.
    packages=['rshell'],

Thanks for all the remote interactivity, Dave! rshell rocks. Let's keep the rock alive as we leap into 2022.