Filename generation bug

Hello, I just found an error in the filename generation here:

https://plugins.trac.ww.wp.xz.cn/browser/qr-code-generator-by-unitag/trunk/unitag.php#L192

It should be:

$filename = 'qr_' . $type . '_' . md5(json_encode(array($id_template, $size, $data_array))) . '.jpg';

https://ww.wp.xz.cn/plugins/qr-code-generator-by-unitag/