Be more specific about MarkLogic version support

Author: wooldridge

README.md

@@ -15,9 +15,9 @@ from Node.js applications.
 
 ## Status
 
-Release 2.0.1 of the MarkLogic Node.js Client API, compatible with MarkLogic
-versions 8 and 9. To use the new features available in 2.0.1, you will need to
-run MarkLogic version 9.
+Release 2.0.1 of the MarkLogic Node.js Client API, tested to work with MarkLogic
+versions 8.0-6.3 and 9.0-1. To use the new features available in release 2.0.1,
+you will need to run MarkLogic version 9.
 
 ## New Features in Release 2.0.1