Fix sourceMaps urls with Scala 3

Author: japgolly

build.sbt

@@ -37,16 +37,6 @@ homepage := Some(url("http://scala-js.org/"))
 
 licenses += ("MIT", url("http://opensource.org/licenses/mit-license.php"))
 
-scalacOptions ++= {
-  if (isSnapshot.value)
-    Seq.empty
-  else {
-    val a = baseDirectory.value.toURI
-    val g = "https://raw.githubusercontent.com/scala-js/scala-js-dom"
-    Seq(s"-P:scalajs:mapSourceURI:$a->$g/v${version.value}/")
-  }
-}
-
 def hasNewCollections(version: String): Boolean = {
   !version.startsWith("2.11.") &&
   !version.startsWith("2.12.")