fix: Add getAllRoles method to Enforcer facade (#77)

Author: swarakaka

Diff for: src/Facades/Enforcer.php

@@ -6,6 +6,7 @@
 
 /**
  * @see \Casbin\Enforcer
+ * @method static string[] getAllRoles()
  * @method static string[] getRolesForUser(string $name, string ...$domain)
  * @method static string[] getUsersForRole(string $name, string ...$domain)
  * @method static bool hasRoleForUser(string $name, string $role, string ...$domain)