Update 3.5 pointer

Author: tolbertam

docs.yaml

@@ -54,7 +54,7 @@ api_docs:
   2.0: http://docs.datastax.com/en/drivers/java/2.0
 versions:
   - name: '3.5'
-    ref: '3.5.1'
+    ref: '3.5.x'
   - name: '3.4'
     ref: '3.4.x'
   - name: '3.3'