update readme.rst with latest package

Author: Ravi kumar

README.rst

@@ -14,9 +14,10 @@ forex-python
 .. image:: https://img.shields.io/badge/python-2.7%2C%203.3%2C%203.4%2C%203.5-blue.svg
     :target: https://pypi.python.org/pypi/forex-python
 
-
 Forex Python is a Free Foreign exchange rates and currency conversion.
 
+**Note: Install latest forex-python==1.0.0 to avoid RatesNotAvailableError**
+
 Features:
 ---------
 - List all currency rates.