Merge pull request com-lihaoyi#244 from japgolly/topic/scala-3.0.0-RC3

Upgrade to Scala 3.0.0-RC3

Author: japgolly

build.sc

@@ -4,12 +4,12 @@ import de.tobiasroeser.mill.vcs.version.VcsVersion
 
 val dottyVersions = sys.props.get("dottyVersion").toList
 
-val scalaVersions = "2.11.12" :: "2.12.13" :: "2.13.4" :: "3.0.0-RC2" :: dottyVersions
+val scalaVersions = "2.11.12" :: "2.12.13" :: "2.13.4" :: "3.0.0-RC3" :: dottyVersions
 val scala2Versions = scalaVersions.filter(_.startsWith("2."))
 
 val scalaJSVersions = for {
   scalaV <- scalaVersions
-  scalaJSV <- Seq("0.6.33", "1.4.0")
+  scalaJSV <- Seq("0.6.33", "1.5.1")
   if scalaV.startsWith("2.") || scalaJSV.startsWith("1.")
 } yield (scalaV, scalaJSV)