Update README.md

Author: NickColley

README.md

@@ -2,7 +2,7 @@
 
 Node.js API for GOV.UK Content and Search APIs.
 
-[![GOVUK API latest npm version](https://img.shields.io/npm/v/@nickcolley/govuk.svg)](https://www.npmjs.com/package/@nickcolley/govuk)
+[![GOVUK API latest npm version](https://img.shields.io/npm/v/@nickcolley/govuk.svg?v=2)](https://www.npmjs.com/package/@nickcolley/govuk)
 
 ## Getting started