chore: add Next.js package in README (#1068)

Co-authored-by: Ruben Izmailyan <rubendinho@users.noreply.github.com>

Author: subzero10

README.md

@@ -8,7 +8,7 @@ You can refer to the README of each package for more information and instruction
   [![npm version](https://badge.fury.io/js/%40honeybadger-io%2Fcore.svg)](https://badge.fury.io/js/%40honeybadger-io%2Fcore)  
   The core package that integrates with Honeybadger API
 - [@honeybadger-io/js](./packages/js)  
-  [![npm version](https://badge.fury.io/js/%40honeybadger-io%2Fjs.svg)](https://badge.fury.io/js/%40honeybadger-io%2Fjs)
+  [![npm version](https://badge.fury.io/js/%40honeybadger-io%2Fjs.svg)](https://badge.fury.io/js/%40honeybadger-io%2Fjs)  
   SDK for browser, nodejs and AWS Lambda 
 - [@honeybadger-io/webpack](./packages/webpack)  
   [![npm version](https://badge.fury.io/js/%40honeybadger-io%2Fwebpack.svg)](https://badge.fury.io/js/%40honeybadger-io%2Fwebpack)  
@@ -19,6 +19,9 @@ You can refer to the README of each package for more information and instruction
 - [@honeybadger-io/react](./packages/react)  
   [![npm version](https://badge.fury.io/js/%40honeybadger-io%2Freact.svg)](https://badge.fury.io/js/%40honeybadger-io%2Freact)  
   SDK for React integration
+- [@honeybadger-io/nextjs](./packages/nextjs)  
+  [![npm version](https://badge.fury.io/js/@honeybadger-io%2Fnextjs.svg)](https://badge.fury.io/js/@honeybadger-io%2Fnextjs)  
+  SDK for Next.js integration
 - [@honeybadger-io/gatsby-plugin-honeybadger](./packages/gatsby-plugin)  
   [![npm version](https://badge.fury.io/js/%40honeybadger-io%2Fgatsby-plugin-honeybadger.svg)](https://badge.fury.io/js/%40honeybadger-io%2Fgatsby-plugin-honeybadger)  
   [Gatsby](https://www.gatsbyjs.com) plugin