Update README.rst (#608)

Co-authored-by: Axel Suárez <axsuarez@microsoft.com>

Author: Kyle Delaney

libraries/botframework-connector/README.rst

@@ -39,9 +39,9 @@ Client creation (with authentication), conversation initialization and activity
 
 .. code-block:: python
 
-  from microsoft.botbuilder.schema import *
-  from microsoft.botframework.connector import ConnectorClient
-  from microsoft.botframework.connector.auth import MicrosoftTokenAuthentication
+  from botbuilder.schema import *
+  from botframework.connector import ConnectorClient
+  from botframework.connector.auth import MicrosoftAppCredentials
 
   APP_ID = '<your-app-id>'
   APP_PASSWORD = '<your-app-password>'
@@ -50,7 +50,7 @@ Client creation (with authentication), conversation initialization and activity
   BOT_ID = '<bot-id>'
   RECIPIENT_ID = '<user-id>'
 
-  credentials = MicrosoftTokenAuthentication(APP_ID, APP_PASSWORD)
+  credentials = MicrosoftAppCredentials(APP_ID, APP_PASSWORD)
   connector = ConnectorClient(credentials, base_url=SERVICE_URL)
 
   conversation = connector.conversations.create_conversation(ConversationParameters(
@@ -130,4 +130,4 @@ Licensed under the MIT_ License.
 .. _MSRC PGP: https://technet.microsoft.com/en-us/security/dn606155
 .. _Security TechCenter: https://github.com/Microsoft/vscode/blob/master/LICENSE.txt
 
-.. <https://technet.microsoft.com/en-us/security/default>`_
+.. <https://technet.microsoft.com/en-us/security/default>`_