Merge pull request #9 from julienrf/use-M4-pre-20d3c21

Use scalaVersion 2.13.0-M4-pre-20d3c21

Author: julienrf

build.sbt

@@ -4,12 +4,10 @@ name := "scala-collection-compat"
 
 version := "0.1-SNAPSHOT"
 
-resolvers += "scala-pr" at "https://scala-ci.typesafe.com/artifactory/scala-integration/"
-
 unmanagedSourceDirectories in Compile ++=
   (if(scalaVersion.value.startsWith("2.13.")) Seq((sourceDirectory in Compile).value / "scala-2.13") else Seq())
 
-crossScalaVersions := Seq("2.12.4", "2.13.0-pre-c577876")
+crossScalaVersions := Seq("2.12.4", "2.13.0-M4-pre-20d3c21")
 
 scalaVersion := crossScalaVersions.value.head