Change format of badges in README from .md to .rst (#1212)

Author: bschoening

README.rst

@@ -1,5 +1,10 @@
-[![License](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://opensource.org/licenses/Apache-2.0)
-[![PyPI version](https://badge.fury.io/py/cassandra-driver.svg)](https://badge.fury.io/py/cassandra-driver)
+
+.. |license| image:: https://img.shields.io/badge/License-Apache%202.0-blue.svg
+    :target: https://opensource.org/licenses/Apache-2.0
+.. |version| image:: https://badge.fury.io/py/cassandra-driver.svg
+    :target: https://badge.fury.io/py/cassandra-driver
+
+|license| |version|
 
 DataStax Driver for Apache Cassandra
 ====================================