Docs: What's new? misformatted

[bradyrx]

I've noticed for awhile now that the "What's new?" page is not properly formatted: https://ultraplot.readthedocs.io/en/latest/whats_new.html. It makes it hard to read and see all of the exciting stuff being released!

• Markdown headers not properly formatting
• Images not embedding correctly
• Code blocks rendering improperly

[cvanelteren]

Thanks! We automatically generate this from the release pages on GitHub. Will need to do some post processing to fix this.