Update README with npm version badge

Add npm version badge to README

Author: seveibar

README.md

@@ -2,6 +2,9 @@
 
 Convert EasyEDA JSON PCB footprints into [Circuit JSON](https://github.com/tscircuit/circuit-json) or TypeScript React components.
 
+[![npm version](https://img.shields.io/npm/v/easyeda.svg)](https://www.npmjs.com/package/easyeda)
+
+
 ```bash
 npm install -g easyeda
 ```