This blog is Gatsby built based on https://github.com/alxshelepenok/gatsby-starter-lumen It was adjusted to work with Gatsby adoc documents (plugin gatsby-transformer-asciidoc).
More on the Asciidoctor setup can be found at https://blog.chalda.cz/posts/gatsby-and-asciidoc
Working with custom DNS domain http://blog.chalda.cz.
See info on custom domains with github pages at https://docs.github.com/en/pages/configuring-a-custom-domain-for-your-github-pages-site/managing-a-custom-domain-for-your-github-pages-site
Using Github actions, see ./.github/workflows/gatsby.yml.