Special chars in Order Info will cause signature calculating failed

[MrCorncob]

$orderInfo with special characters will render invalid when receiving response after successful payment.
Example:

$orderInfo = 'foo & bar';
$momoCaptureResponse = CaptureMoMo::process(
        $env,
        sprintf('MOMO-%s-%s', $order_id, time() . ""),
        $orderInfo,
        sprintf('%0d', $order_info['total']),
        "cs_order_id=" . $order_id,
        $requestId,
        $notify_url,
        $return_url
    );