Do we really want to delete all this? Suggest we keep the info about previous versions (0.5.0-rc.1 and 0.5.0-M2) as well. And only get rid of them when we have an official 0.5.0 release.

Suggest we PR this into the 0.5 branch. I think we can merge that before we have the 0.5.0-rc.2 release; the text will therefore end up in the 0.5.0-SNAPSHOT and the 0.5.0-rc.2 branches which is fine. Before we can release a 0.5.0 then we'll need to update this text again to just have the 0.5.0 release notes.