Downgrade referenceVersion to 3.6.0 (assuming 3.6.0-RC1) to use experimental TASTy version in main. Add notes on how referenceVersion should be tracked

Author: WojciechMazur

Diff for: project/Build.scala

@@ -91,7 +91,12 @@ object DottyJSPlugin extends AutoPlugin {
 object Build {
   import ScaladocConfigs._
 
-  val referenceVersion = "3.6.1"
+  /** Version of the Scala compiler used to build the artifacts.
+   *  Reference version should track the latest version pushed to Maven:
+   *  - In main branch it should be the last RC version (using experimental TASTy required for non-bootstrapped tests)
+   *  - In release branch it should be the last stable release
+   */
+  val referenceVersion = "3.6.0"
 
   val baseVersion = "3.6.2"
   // Will be required by some automation later