Planning a release for 2.1.20

[lppedd]

Now that we're approaching 2.1.21, it might be a good idea to release the current status.

I'm also planning to update my 1.9.24 codebase to 2.1.20, and having kotlin-multiplatform-diff on 2.1.20 is a prerequisite.

[petertrr]

Hey @lppedd, I've just published 1.1.0-rc.1, built with Kottin 2 and using cross compilation. Would be great if you could test it in your projects. And I'll just publish the final version in a couple of days; I don't expect anything to break

[lppedd]

Hey @petertrr, will do! I need to get Strumenta/antlr-kotlin#204 merged and released, and then I can begin testing.