update index of old docs

Author: markxnelson

site/README.md

@@ -8,6 +8,10 @@ If you wish to view documentation for an older version, please see:
 * [Version 1.0](v1.0)
 * [Version 1.1](v1.1)
 * [Version 2.0](v2.0)
-* [Version 2.0.1](v2.0.1)
+* In Version 2.0.1, we migrated from using plain Markdown on GitHub to 
+  a new documentation site built using Hugo and served by GitHub pages.
+  Both versions are archive here:
+    * [Old Version 2.0.1](v2.0.1)
+    * [New Version 2.0.1](https://oracle.github.io/weblogic-kubernetes-operator/2.0.1)
 
 For a guide to the operator project, refer to this [README](../README.md).