Make laravel 8 compatible

Author: Shivella

composer.json

@@ -12,7 +12,7 @@
   ],
   "require": {
     "php": ">=5.5.9",
-    "illuminate/support": "^5.1|^6|^7",
+    "illuminate/support": "^5.1|^6|^7|^8",
     "api-postcode/php-client": "^1.0"
   },
   "autoload": {