Update release github action

[india-kerle]

We need to update that action + pushing to pypi more generally so that:

• it installs requirements in requirements_dev.txt
• update this gist to formalise how we push to pypi a bit more

[Aiden-RC]

Looking at that gist and the workflow file the majority of it can be automated really.
Gist changes:

• no longer need to change version in setup.py as getting it from setup tools

• can also switch docs/source/conf.py version to use the same function

• re-building documentation can be done automatically: https://github.com/marketplace/actions/sphinx-build

• you can build a changelog by requiring PR's to have a description of changes contained and compiling all the PR changelogs together between releases ( see: https://github.com/semantic-release/release-notes-generator )

or you can simply use something like this: https://github.com/semantic-release/semantic-release to automate well everything needed to release from triggering document building to release notes to deployment triggers