Prepare for use with Jupyter Releaser

[davidbrochart]

Closes #70

[davidbrochart]

This last commit prepares fps-auth for use with Jupyter Releaser, but I'm not sure that's the way to go. In particular, I'm wondering if we will have a global jupyverse release that will also release all the plugins, or if jupyverse and each plugin will be released independently. In the former case, that would mean whenever there is a change in jupyverse or in one of the its plugins, all plugins will be released even if they don't change. In the later case, I'm wondering if it makes sense to have the plugins in this repo then, or each one in their own repo.

[jtpio]

wondering if we will have a global jupyverse release that will also release all the plugins, or if jupyverse and each plugin will be released independently

This sounds similar to JavaScript monorepos, with the tradeoff between managing each package independently (in its own repo) vs in a monorepo.

Probably the plugins could still live in the same repo. The bump version script could check whether a plugin has changed and bump the version accordingly. Or all plugins follow the same cycle for patch and build increments, and are versioned independently for minor and major bumps (that might be simpler).

[davidbrochart]

I'm going to merge this PR, even though the "Check Release" actions fail, and iterate on jupyter-server/jupyter_releaser#176 until we get Jupyter Releaser to work on this repo.