Weaken the plugin attribute in Role::Provider to avoid mem cycle

Author: SysPete

lib/Dancer2/Plugin/Auth/Extensible/Role/Provider.pm

@@ -30,6 +30,7 @@ Required.
 has plugin => (
     is       => 'ro',
     required => 1,
+    weaken   => 1,
 );
 
 =head2 disable_roles