Add a GitHub Action

[mgeisler]

We should publish our own GitHub Action to make it easy to use mdbook-i18n-helpers.

This will move logic from the YAML file (such as publish.yml) to the action. The action is probably written in TypeScript (I'm not sure we can write an action in Rust?) and this will be a more comfortable language than what we can do with scripts in the YAML file.

[mgeisler]

What should a GitHub action do?

• it should download a pre-compiled mdbook-gettext binary so that mdbook build can be fast.
• when Build translations from mdbook #84 is done, the action should also download a pre-compiled version of the new binary there.

Where do these pre-compiled binaries come from? We will need to generate and publish them as part of a release workflow for this repository. See #78 for another issue about releasing binaries.

I would like us to use mgeisler/rust-release-gh-action to do the releases — it's the release flow I'm using for all my Rust crates these days. This release workflow needs to be integrated and it needs to be extended to generate binaries. It should probably also be rewritten as a Rust binary instead (which we will execute via a Dockerfile GitHub action.

So, all in all, there is a fair amount of steps to be tackled here by someone... it will involve touching several interesting technologies 😄

[trooper2013]

@mgeisler Could you please assign this task to me.

[mgeisler]

Hey @trooper2013, thanks a lot for looking at this!

I would love for you to start simple here: building a fully automatic publishing pipeline is complicated, but making a very simple GitHub action is not.

See https://github.com/dprint/check as a good example of how to get started. The action.yml file there installs the dprint command line and runs it. In our case, "installing" means running cargo install mdbook-i18n-helpers at first 🙂