Set version developed on main as 3.4.2 (#19683)

Author: Kordyjan

project/Build.scala

@@ -85,7 +85,7 @@ object Build {
 
   val referenceVersion = "3.3.1"
 
-  val baseVersion = "3.4.1-RC1"
+  val baseVersion = "3.4.2-RC1"
 
   // Versions used by the vscode extension to create a new project
   // This should be the latest published releases.