How do I write a 150 page book in Markdown using github as version control then output to a designed .pdf whenever I want to release?

I'm looking for a toolchain and workflow for version control and Continuous Integration / Continuous Deployment for a book of prose.

some tools I've looked at:

• gitbook
• docusaurus
• sphinx
• pandoc

I want to output to .mobi .epub and .pdf … and have the document be pretty and designed, with cover, in context illustrations, and tables.

Can anyone point me in the right direction?

Thank you. :)