Allow laravel 6

Author: JeroenBoesten

composer.json

@@ -17,7 +17,7 @@
     ],
     "require": {
         "php": "^7.1",
-        "illuminate/support": "5.8.* || 5.7.*"
+        "illuminate/support": "^6.0.0 || 5.8.* || 5.7.*"
     },
     "require-dev": {
         "orchestra/testbench": "3.8.*",