The answer is:
I’m not sure I’m going to have time to look at it in the next few days, but since my blog also uses Jekyll, it should be easy for someone to just copy the source code: https://github.com/soonick/soonick.github.io/blob/master/_posts/2020-06-10-create-diagrams-with-code-using-graphviz.md . I would appreciate a link to the original article.
If you guys can’t do it, I can put it in my todo list and take care of it in the next few weeks.
Regards,
Adrian