Add the jetbrains official maven repo

Jetbrains and Google are developing a new open source Multiplatform UI library called "Compose Multiplatform" that I expect more and and more apps will be using.

The library is licensed Apache 2.0, and code is available here: https://github.com/JetBrains/compose-multiplatform

The maven repo it lives in is here: https://maven.pkg.jetbrains.space/public/p/compose/dev