feat: update casbin to v3.0

Author: leeqvip

composer.json

@@ -20,13 +20,13 @@
     ],
     "license": "Apache-2.0",
     "require": {
-        "casbin/casbin": "~2.1",
+        "casbin/casbin": "~3.0",
         "topthink/framework": "^6.0.0",
         "topthink/think-migration": "^3.0",
         "casbin/psr3-bridge": "^1.1"
     },
     "require-dev": {
-        "phpunit/phpunit": "~7.0",
+        "phpunit/phpunit": "~7.0|~8.0",
         "php-coveralls/php-coveralls": "^2.1",
         "topthink/think": "^6.0.0"
     },