Guide should explain "making a release"

[n8willis]

Since the GitHub workflow in the project template has a "'create and populate release" job, the guide should explain how to do that.

Specifically, the problem encountered in Agu Display is that the workflow only accepts pure decimal numbers as the tag — so not "v1.0" and no "1.0.1" either.

The reason that needs explaining is that GitHub's "draft a new release" page specifically advises the user to both use a "v" and to use three-part semver version numbers.... So if doing that is going to break things, designers will need to be told what they should do instead.

(Screenshot of GitHub UI; see RHS column::)