GitHub Actions setup guide

[Andre601]

It could be useful to provide a small guide on how to integrate automatic, scheduled updating of robots.txt from this repository using GitHub Actions.

Main reason is, that many people probably use GitHub pages to host their site and probably want to automate updating their robots.txt.
Since GH Actions can trigger workflows now, I think it is technically doable to create an update action that would trigger a follow-up publish action from a push.

The only workflow I can propose is from my own website, which isn't hosted on GitHub, but should be mostly compatible (there may be easier aproaches with GitHub Actions itself).
It can be found here: https://codeberg.org/Andre601/website/src/branch/main/.forgejo/workflows/update_robots.yml

[glyn]

I agree that such a guide would be useful, but perhaps another for codeberg would be useful too. In that case, you could perhaps submit a PR for that.