pyinstaller packages up all of a python script's dependencies and builds them into standalone executables. It can either do a directory (containing a single executable and a bunch of shared libraries) or a self-contained executable that effectively just contains a compressed version of the directory.
The problem is, if you have several scripts like we do, you get several large directories or standalone binaries, and there's a ton of duplication between them. Fortunately it looks like using the directory method and just combining the directories works fine (for this project).
This PR runs the above build on any tagged commit and publishes a release in github containing the pyinstall-ified tarball. If the tag is named like "v1.2.3" _and_ the tag is on the master branch, then the github release will be marked as "production". Otherwise, it will be marked as a "pre-release". This means that we can build testable tarballs of the extension in a pull request by tagging a commit.
Lex Neva