If this ModuleID cross-version is a Dotty version, replace it by the Scala 2.
If this ModuleID cross-version is a Dotty version, replace it by the Scala 2.x version that the Dotty version is retro-compatible with, otherwise do nothing.
This setting is useful when your build contains dependencies that have only been published with Scala 2.x, if you have:
libraryDependencies += "a" %% "b" % "c"
you can replace it by:
libraryDependencies += ("a" %% "b" % "c").withDottyCompat()
This will have no effect when compiling with Scala 2.x, but when compiling with Dotty this will change the cross-version to a Scala 2.x one. This works because Dotty is currently retro-compatible with Scala 2.x.
NOTE: Dotty's retro-compatibility with Scala 2.x will be dropped before Dotty is released, you should not rely on it.