Revert "Target minor version"

This reverts commit e96f653.
Since we are now our own branch on origin, there's no need to deviate
in targeting a minor version. We are targeting no specific version
at the present time, so there's no need to deviate from the standard
build

Author: odersky

project/Build.scala

@@ -65,7 +65,7 @@ object DottyJSPlugin extends AutoPlugin {
 object Build {
   val referenceVersion = "3.0.0"
 
-  val baseVersion = "3.1.0-RC1"
+  val baseVersion = "3.0.2-RC1"
 
   // Versions used by the vscode extension to create a new project
   // This should be the latest published releases.