support php version 8.0 or more (#72)

Author: maherelgamil

composer.json

@@ -53,7 +53,7 @@
         "docs": "https://github.com/cybercog/laravel-eloquent-flag/wiki"
     },
     "require": {
-        "php": "^7.1.3|8.0",
+        "php": "^7.1.3|^8.0",
         "illuminate/database": "^5.8|^6.0|^7.0|^8.0"
     },
     "require-dev": {