[announcement]: alternative to openvsx for self-hosting a marketplace

Howdy from Coder!

Today we are open-sourcing https://github.com/coder/code-marketplace which provides an easier way to self-host your own marketplace. See https://coder.com/blog/running-a-private-vs-code-extension-marketplace for more specifics.

question: do you want a pull-request with this information added to the README? If so, under which section.