[Housekeeping] Versioned docs

[RasmusKjeldgaard]

• I have written a good issue

Describe the housekeeping request

Teams will often be using slightly older versions of Kirby in their products, because their update cycle is, of course, different from our release cycle.

Because we currently only document the latest version on https://cookbook.kirby.design, developers get confused that sometimes the documented way of doing things is not working for them, because they are on an earlier version.

Nathan Curtis has some thoughts on why this makes sense too: https://medium.com/eightshapes-llc/versioning-design-systems-48cceb5ace4d

Have you considered any alternatives?

No, but we should consider if it is worth the effort.
But I do think this could be done faily easily, by publishing github page similar to our dev branches, but on the same trigger as we use for the publish script.

So when a new tag is added to the develop-branch, we automatically publish to github pages on https://cookbook.kirby.design/v1.2.3.