[FEAT] Add RSS autodiscover tag and/or direct link

[bskinn]

No problem at all, @kalvdans! That autodiscover tag sounds like something we should add, as well as a direct RSS link in the footer, probably.

The feed is at https://labs.quansight.org/rss.xml.

Thanks for your interest!

Originally posted by @bskinn in #403 (comment)