Correct npm badge link (#296)

README.md

@@ -3,7 +3,7 @@
 
 [![Master Build](https://travis-ci.org/improbable-eng/grpc-web.svg)](https://travis-ci.org/improbable-eng/grpc-web)
 ![BrowserStack Status](https://www.browserstack.com/automate/badge.svg?badge_key=L0k3QjhiNnByd3hWVVhtS0FxTmNrZERwbDBqR053OFJKV01veUpkL1FqOD0tLXZyS0d2WC9TaGEzeTBjbXZ6L1JNa2c9PQ==--b460187586f63fc2a48f557a515f9900f5639d10)
-[![NPM](https://img.shields.io/npm/v/grpc-web-client.svg)](https://www.npmjs.com/package/grpc-web-client)
+[![NPM](https://img.shields.io/npm/v/@improbable-eng/grpc-web.svg)](https://www.npmjs.com/package/@improbable-eng/grpc-web)
 [![GoDoc](http://img.shields.io/badge/GoDoc-Reference-blue.svg)](https://godoc.org/github.com/improbable-eng/grpc-web/go/grpcweb) 
 [![Apache 2.0 License](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](LICENSE)
 [![quality: alpha](https://img.shields.io/badge/quality-alpha-orange.svg)](#status)