Just fork the repo, configure and customize, then push it back up for GitHub Pages.
I’ve seen more and more people jump ship from Jekyll due to performance. Paul Robert Lloyd migrated over to Eleventy, even I’m contemplating something else. Interestingly enough, the static site generator comparisons mostly have to do with developer ergonomics because they all essentially do the same thing: output static HTML.
Parker Moore joined the show to talk with Adam about blogging for hackers with Jekyll and GitHub Pages.