Add support to Laravel 8.x on composer.json (#15)

Author: icaroscherma

composer.json

@@ -23,7 +23,7 @@
   },
   "require": {
        "php": "7.2.*|7.3.*|7.4.*",
-       "laravel/framework": "~5.1|6.*|7.*"
+       "laravel/framework": "~5.1|6.*|7.*|8.*"
   },
   "autoload-dev": {
     "classmap": [