since yarn is strongly inspired &based on npm i think the process would mostly be identical, although it would be nice if Idris write a separate post specified to yarn :)
I haven't done anything with Yarn yet, but from what I've seen on it, the process is mostly the same with one just needing to substitute with equivalent Yarn commands.
You know, now that you've mentioned it, I just may write an article for Yarn too. 🤔
Publishing to npm is publishing to yarn as far as I know. Just publish the package to npm and it shows up in yarn in some time. I've written an article about creating cli apps, updating them and managing releases too. If you're interested, you can view it here