Add CDNJS version badge in readme (#289)

Author: PeterDaveHello

README.md

@@ -1,5 +1,6 @@
 ## jQuery Date Range Picker Plugin
 
+[![CDNJS](https://img.shields.io/cdnjs/v/jquery-date-range-picker.svg)](https://cdnjs.com/libraries/jquery-date-range-picker)
 [![Bower Version](https://img.shields.io/bower/v/jquery-date-range-picker.svg?maxAge=3600)]()
 [![License](https://img.shields.io/github/license/longbill/jquery-date-range-picker.svg?maxAge=2592000)]()