Daniel Bachhuber wrote a blog post on how to convert a shortcode to a block to embed a Github Gist into a post. We used it in our post about Lara Schenck's developer talk at Hollywood WordPress Meetup.
- Daniel Bachhuber: How to Convert a Shortcode to a Gutenberg Block
- Demo Code on GitHub /pantheon-systems/github-gist-gutenberg-block
Now also available in the public WordPress plugin repository: