Add support laravel v8.x

Author: metallurgical

composer.json

@@ -4,10 +4,10 @@
     "keywords": ["kasitaw", "api-key", "api-integration", "api"],
     "require": {
         "php": ">=7.2",
-        "illuminate/support": "^7.0"
+        "illuminate/support": "^7.0|^8.0"
     },
     "require-dev": {
-        "laravel/framework": "^7.0",
+        "laravel/framework": "^7.0|^8.0",
         "phpunit/phpunit": "^8.0|^9.0",
         "orchestra/testbench": "^5.0",
         "friendsofphp/php-cs-fixer": "^2.16"