Update scala 2.13.0-M5 to 2.13.0-RC1

Author: Philippus

build.sbt

@@ -4,7 +4,7 @@ scalaModuleSettings
 
 scalaVersionsByJvm in ThisBuild := {
   val v212 = "2.12.8"
-  val v213 = "2.13.0-M5"
+  val v213 = "2.13.0-RC1"
 
   val allFalse = List(v212 -> false, v213 -> false)
   Map(