add `-Xsource:3` to help cross compiles to js/native

[He-Pin]

eg:
Allow import x.{*, given} under -Xsource:3 (scala/scala#9736 by @smarter)

And then , we can use * in import.

[He-Pin]

Just find it's there, but not sure why if * is there then the test fails

[stephenamar-db]

we already have this?

def scalacOptions = super.scalacOptions() ++ (
  if (!ZincWorkerUtil.isScala3(scalaVersion())) Seq("-opt:l:inline", "-opt-inline-from:sjsonnet.*,sjsonnet.**", "-Xsource:3")
  else Seq[String]()
)

[He-Pin]

Yes, but if the ☆ in import, the native and js tests fails in ci

[stephenamar-db]

fixed the title