Revert "Set referenceVersion to 3.6.2-RC1"

This reverts commit 8a08245.

Author: WojciechMazur

project/Build.scala

@@ -97,7 +97,7 @@ object Build {
    *  - In release branch it should be the last stable release
    *  3.6.0-RC1 was released as 3.6.0 - it's having and experimental TASTy version
    */
-  val referenceVersion = "3.6.2-RC1"
+  val referenceVersion = "3.6.0"
 
   /** Version of the Scala compiler targeted in the current release cycle
    *  Contains a version without RC/SNAPSHOT/NIGHTLY specific suffixes