src\Message\CreateOrderResponse.php中42号中的time改为字符串

修改后代码：
$time = time();
$data = array (
'appId' => $this->request->getAppId(),
'package' => 'prepay_id=' . $this->getPrepayId(),
'nonceStr' => md5(uniqid()),
'timeStamp' => "$time",
'signType' => 'MD5',
);