Allow installation on PHP8

Author: Tjoosten

composer.json

@@ -10,7 +10,7 @@
         }
     ],
     "require": {
-        "php": "^7.1.3|^7.2.5|^7.3",
+        "php": "^7.1.3|^7.2.5|^7.3|^8.0",
         "laravel/ui": "^1.0|^2.0|^3.0",
         "illuminate/console": "~5.8|^6.0|^7.0|^8.0",
         "illuminate/filesystem": "~5.8|^6.0|^7.0|^8.0",