Update 4.0.0 to beta1

Author: olim7t

docs.yaml

@@ -46,7 +46,7 @@ api_docs:
   3.5: http://docs.datastax.com/en/drivers/java/3.5
   3.4: http://docs.datastax.com/en/drivers/java/3.4
   3.3: http://docs.datastax.com/en/drivers/java/3.3
-  4.0-alpha: http://docs.datastax.com/en/drivers/java/4.0
+  4.0-beta: http://docs.datastax.com/en/drivers/java/4.0
   3.2: http://docs.datastax.com/en/drivers/java/3.2
   3.1: http://docs.datastax.com/en/drivers/java/3.1
   3.0: http://docs.datastax.com/en/drivers/java/3.0
@@ -59,8 +59,8 @@ versions:
     ref: '3.4.0_docfixes'
   - name: '3.3'
     ref: '3.3.2'
-  - name: '4.0-alpha'
-    ref: '4.0.0-alpha3'
+  - name: '4.0-beta'
+    ref: '4.0.0-beta1'
     prerelease: true
   - name: '3.2'
     ref: '3.2_docfixes'