Need to document versioning spec

[0Hughman0]

Currently, what I'm trying to do is:

We have a branch for each minor version e.g. 0.1.x and 0.2.x, the head of which should always be the latest patch of that minor release.

For development, I think we specify the whole planned version number, but add -pre for pre-release e.g. 0.2.4-pre.

We then create branches for implementing specific features, and submit PRs into those pre-release branches as progress is made.

If necessary, we publish a pre-release version, but within pyproject.toml will have to use the poetry spec:

https://python-poetry.org/docs/cli/#version

e.g. the version would be something like 0.2.4a0 for the first pre-release.

Once we are happy with the pre-release, it can be merged (via PR) into the appropriate minor version branch and the pre-release branch can be deleted.

[0Hughman0]

Workflows need to be updated to allow actions to run appropriately.

[0Hughman0]

Workflows fixed in #111

Documentation added in #112