Update README.md

Author: Guillaume Badi

README.md

@@ -1,7 +1,9 @@
-#Simple Mailjet APIv3 wrapper (WIP)
+#Simple Mailjet APIv3 wrapper
 
 [![Build Status](https://travis-ci.org/mailjet/mailjet-apiv3-python.svg?branch=master)](https://travis-ci.org/mailjet/mailjet-apiv3-python)
 
+Compatibility: python2.*
+
 ### API documentation
 
 Every code examples can be find on the Mailjet Documentation: http://dev.mailjet.com/guides/?python