Automatic documentation upload to gh-pages branch

[hugopl]

Currently, the documentation at https://hugopl.github.io/gtk4.cr/ is made "manually", I mean... every time I need to update it I do:

git checkout gh-pages
git rm doc
git merge WHATEVER_NEW_VERSION
make doc
git add doc
git push origin gh-pages

These are simple and static steps that can be automatized by a github actions that runs every time a new tag is created in the repository.

[1player]

I started working on this on my local fork, mostly to familiarise myself with Github Actions, but the latest Ubuntu version they provide workers for is 20.04 LTS which doesn't ship with gtk4. I've read they'll have Ubuntu 22.04 LTS in preview state some time in May, so I guess this is on hold until then.

actions/runner-images#5428

[1player]

Apparently Ubuntu 22.04 is now available: actions/runner-images#5490 so this is now possible. I'll have a jab at it next week.

[GeopJr]

I usually use peaceiris/actions-gh-pages for publishing docs since it handles a lot from checking whether anything actually changed to removing all commits from the branch so it doesn't clog cloning (and many more):

• from gettext.cr
• Action readme with all the options and example workflows

[1player]

I'm working on it right now, I should have something ready soon.