changed npm directory to 4.0

Author: chasingjohn

README.md

@@ -2,7 +2,7 @@
 
 ![Platform](https://img.shields.io/badge/platform-JAVASCRIPT-orange.svg)
 ![Languages](https://img.shields.io/badge/language-TYPESCRIPT-orange.svg)
-[![npm](https://img.shields.io/npm/v/sendbird.svg?style=popout&colorB=red)](https://www.npmjs.com/package/sendbird)
+[![npm](https://img.shields.io/npm/v/sendbird.svg?style=popout&colorB=red)](https://www.npmjs.com/package/@sendbird/chat)
 
 ## Table of contents