Merge pull request #15 from basakest/UpgradeCasbin

feat: upgrade casbin to 3.1

Author: hsluoyz

composer.json

@@ -11,7 +11,7 @@
     "require": {
         "php": "^7.2",
         "ext-swoole": ">=4.5",
-        "casbin/casbin": "^2.2",
+        "casbin/casbin": "~3.1",
         "easyswoole/orm": "^1.4",
         "easyswoole/easyswoole": "~3.3|~3.4"
     },