Set base version to 3.1.2-RC1

Author: Kordyjan

project/Build.scala

@@ -60,7 +60,7 @@ object DottyJSPlugin extends AutoPlugin {
 object Build {
   val referenceVersion = "3.1.0"
 
-  val baseVersion = "3.1.1-RC1"
+  val baseVersion = "3.1.2-RC1"
 
   // Versions used by the vscode extension to create a new project
   // This should be the latest published releases.