Most (if not all) static site generators work fine with GitHub pages, I’ve used ghp-import before and it works well. I’ve also done it using submodule tricks and that works well too.
I personally use Hugo for my blog, it’s very fast and I can recommend it. But in truth most of them of kind of the same.
One popular trick to automatically build, check and upload your static site is to use travis-ci. It can be set up to upload on every push to the master branch (or any other branch). If you google “hugo travis ci” or “jekyll travis ci”, etc, you should find a bunch of links. It is fiddly to get setup, but it’s a one time thing.
Also, GitHub includes a really good Markdown editor, along with a very easy to use web-based edit and PR generator. You could definitely get the following workflow going:
- contributor edits or creates a Markdown document on GitHub, makes PR.
- repo owner accepts the PR on GitHub
travis-ci automatically builds and publishes the site