Add publish actions

[multimeric]

• Closes [Enhancement] Update PyPi version and Sphinx docs? #262
• Add steps to build docs, publish docs, and publish PyPi
• At minimum, a repo owner will need to add a PYPI_API_TOKEN secret to allow the package publishing.

[multimeric]

I need some help adding the command we use for building wheels. python setup.py sdist_wheel doesn't seem to work.

[multimeric]

I think this will need an update to: https://github.com/giovtorres/docker-centos7-slurm before it will work.

[tazend]

@multimeric

I've already worked on improving the docker-centos7-slurm container setup a bit and adding one for 22.05 - I'll try to get the changes up this weekend as a PR.

In regards to building: I wouldn't ship a prebuilt wheel right now. I would just upload the source distribution as tar.gz, by doing python setup.py sdist.

The User is expected to have a valid libslurm.so installed on the System where pyslurm should run (and potentially point the pyslurm installation to it if it is a custom slurm installation in a unusual path). When a user executes pip install pyslurm, the source will be cythonized and compiled on the Users specific system.

[multimeric]

Great, thanks for the update. Agreed that we don't want to ship binary wheels. I for some reason thought there were source wheels but maybe there aren't, and it's just sdist that we want.

[giovtorres]

Added in #407. Still needs a little work but end to end seems to be working.