Allow free shipping for EDD Simple Shipping

<?php

/**

 * Set the price has shipping to true for a specific item.

 *

 * @param bool $has_shipping Whether the price has shipping.

 * @param int  $item_id      The item ID.

 * @param int  $price_id     The price ID.

 * @return bool

 */

function eddwp_price_has_shipping( $has_shipping, $item_id, $price_id ) {

	$item_with_free_shipping = 1234;

	return (int) $item_id === $item_with_free_shipping ? true : $has_shipping;

}

add_filter( 'edd_simple_shipping_price_has_shipping', 'eddwp_price_has_shipping', 10, 3 );