Drop 3.0.x and pretend it never existed, use 3.1.x for JVM, JS and Native platforms

Scala 3 doesn't allow to call method with parentheses without them. Normally class can extends trait/interface and overwrite their def's using val/override val no matter if def was declared with or without parentheses. However for Scala 3 this is no llonger true. This PR uses a workaround with underscores.

More information can be found at https://www.scala-js.org/news/2021/08/04/announcing-scalajs-1.7.0/#fixes-with-compatibility-concerns