1. "Perfect is the enemy of good."
If the info is intended to be read by humans, keep it in a human-readable format. That way your project is more likely to _have_ a future.
2. Embrace your tooling.
You are keeping it on Github. GH will render Markdown to HTML for you. Use that. Don't keep it in some format it won't render.
3. Choose the right tools.
YAML is for config files. This isn't a config file.
4. Think about what tools you chose and why.
It may be easy to parse YAML with code, but is that significantly different from how easy it is to parse Markdown with code?
Anyway. You do you. I am not telling you what to do or how to do it. I am merely trying to point out flaws with the current approach.