WooCommerce - Add send customer order notes email option

functions.php

<?php
/**
 * This adds an option to send order notes email manually via order actions drop-down.
 */

/**
 * Filter to add a new menu to the dropdown
 *
 * @param array $actions
 * @return array
 */
function add_send_order_notes_email_action( $actions ) {
	$actions['send_customer_order_notes'] = __( 'Email last order note to Customer', 'woocommerce' );
	return $actions;
}
add_filter( 'woocommerce_order_actions', 'add_send_order_notes_email_action', 10, 1 );

/**
 * Hook into newly added send_customer_order_notes to handle sending of customer emails
 *
 * @param $order Order object
 * @return void
 */
function send_order_notes_email ( $order ) {
	// Send the customer new order email.
	WC()->payment_gateways();
	WC()->shipping();
	$latest_notes = wc_get_order_notes( array(
            'order_id' => $order->get_id(),
            'limit'    => 1,
            'orderby'  => 'date_created_gmt',
			'type' => 'customer',
        ));
	foreach ( $latest_notes as $latest_note ) {
			$last_note = $latest_note->content;
		}
	WC()->mailer()->emails['WC_Email_Customer_Note']->trigger(array(
		'order_id' => $order->get_id(),
		'customer_note' => $last_note
	));	

	// Note the event.
	$order->add_order_note( __( 'Order notes manually sent to customer.', 'woocommerce' ), false, true );

	// Change the post saved message.
	add_filter( 'redirect_post_location', array( 'WC_Meta_Box_Order_Actions', 'set_email_sent_message' ) );
}
add_action( 'woocommerce_order_action_send_customer_order_notes', 'send_order_notes_email', 10, 1 );