Release Dotty 0.15.0-RC1

Author: anatoliykmetyuk

project/Build.scala

@@ -32,7 +32,7 @@ object Build {
   val scalacVersion = "2.12.8"
   val referenceVersion = "0.14.0-RC1"
 
-  val baseVersion = "0.15.0"
+  val baseVersion = "0.15.0-RC1"
   val baseSbtDottyVersion = "0.3.2"
 
   // Versions used by the vscode extension to create a new project