rewrite sbt task cmd in mill build

[mullerhai]

I have some question , some sbt build cmd for scala native task how to write in mill , like this code ,

// import to add Scala Native options
import scala.scalanative.build._

// defaults set with common options shown
nativeConfig ~= { c =>
  c.withSourceLevelDebuggingConfig(SourceLevelDebuggingConfig.enabled)
}

val buildBinary = taskKey[Unit]("")
Global / buildBinary := {
  IO.copyFile(
    (Compile / nativeLink).value,
    baseDirectory.value / "debug-binary"
  )
}