Added NPM page link to README

Author: Cristin O'Connor

README.md

@@ -3,6 +3,7 @@
 <img alt="Screenshot of component" src="https://raw.githubusercontent.com/cnocon/react-github-stats-card-v2/master/component-screenshot.png" width="320"/>
 
 [Demo Site here](https://react-github-stats-card-v2-demo.netlify.app/)
+[NPM Page](https://www.npmjs.com/package/react-github-stats-card-v2)
 
 ### Installation