Fix: update README to include Python 2 support. (#231)

Author: andrewsg

packages/google-cloud-ndb/README.md

@@ -1,8 +1,8 @@
-# Google Datastore `ndb` Client Library
+# Google Cloud Datastore `ndb` Client Library
 
 ## Introduction
 
-This is a Python 3 version of the `ndb` client library for use with
+This is an updated version of the `ndb` client library for use with
 [Google Cloud Datastore][0]. 
 
 * [Client Library Documentation](https://googleapis.dev/python/python-ndb/latest)
@@ -11,7 +11,7 @@ The original Python 2 version of `ndb` was designed specifically for the
 [Google App Engine][1] `python27` runtime and can be found at
 https://github.com/GoogleCloudPlatform/datastore-ndb-python. This version of
 `ndb` is designed for the [Google App Engine Python 3 runtime][2], and will
-run on other Python 3 platforms as well.
+run on other Python platforms as well.
 
 [0]: https://cloud.google.com/datastore
 [1]: https://cloud.google.com/appengine
@@ -21,7 +21,5 @@ run on other Python 3 platforms as well.
 
 Beta
 
-### Supported Python Versions
-Python >= 3.6
-
-Python 2 backwards-compatibility is currently in development.
+### Officially Supported Python Versions
+Python 2.7 & Python 3.6-3.7