Investigate publishing pre-release (nightly) to PyPi

via @psinger

PyPi currently supports `pip install --pre` which installs a prerelease version of the package if provided. This would improve the DX of using nightly as a separate manual download would no longer be needed.

## TODO

Read up more on how (or if) version rotation works in PyPi.

Start by researching how PyPI handles prerelease versions and version rotation, as requested in the TODO. Then inspect the project's existing nightly publishing process and determine whether it can publish a version installable with pip install --pre. Done means the versioning and publishing approach is documented and the nightly package is available through PyPI.

Written by the indexing model from the issue text.