Example on the ReadMe to update order status is incorrect

The example is:

```
$updateInfo = array (
    "fulfillment_status" => "fulfilled",
);

$shopify->Order($orderID)->put($order);
```

I'd assume it should be:

```
$updateInfo = array (
    "fulfillment_status" => "fulfilled",
);

$shopify->Order($orderID)->put($updateInfo);

```

However Shopify still just returns order information as if it is a GET request. 