Fix laravel version & badge.

Add laravel 8 on version compatibility matrix.

Author: jaydons

README.md

@@ -4,7 +4,7 @@
 [![Donate](https://img.shields.io/badge/donate-paypal-blue.svg)](https://www.paypal.me/yajra)
 [![Donate](https://img.shields.io/badge/donate-patreon-blue.svg)](https://www.patreon.com/bePatron?u=4521203)
 
-[![Laravel 4.2|5.x|6.x](https://img.shields.io/badge/Laravel-4.2|5.x-orange.svg)](http://laravel.com)
+[![Laravel 4.2|5.x|6|7|8](https://img.shields.io/badge/Laravel-4.2|5.x|6|7|8-orange.svg)](http://laravel.com)
 [![Latest Stable Version](https://img.shields.io/packagist/v/yajra/laravel-datatables-oracle.svg)](https://packagist.org/packages/yajra/laravel-datatables-oracle)
 [![Latest Unstable Version](https://poser.pugx.org/yajra/laravel-datatables-oracle/v/unstable.svg)](https://packagist.org/packages/yajra/laravel-datatables-oracle)
 [![Build Status](https://travis-ci.org/yajra/laravel-datatables.svg?branch=master)](https://travis-ci.org/yajra/laravel-datatables)
@@ -30,7 +30,7 @@ return datatables(User::all())->toJson();
 
 ## Requirements
 - [PHP >= 7.0](http://php.net/)
-- [Laravel 5.x|6.x](https://github.com/laravel/framework)
+- [Laravel 4.2|5.x|6|7|8](https://github.com/laravel/framework)
 - [jQuery DataTables v1.10.x](http://datatables.net/)
 
 ## Documentations
@@ -60,6 +60,7 @@ return datatables(User::all())->toJson();
  5.8.x    | 9.x
  6.x.x    | 9.x
  7.x.x    | 9.x
+ 8.x.x    | 9.x
 
 ## DataTables 8.x Upgrade Guide
 There are breaking changes since DataTables v8.x.