Fix for quantity increment or decrement button doesn't trigger dynamic strikeout price

Fix quantity button not triggering dynamic strikeout price update.

add_action('wp_head', function (){
    ?>
    <script>
        (function ($) {
            $(document).ready(function ($) {
                $(document).on('click', '.plus, .minus', function (){
                    $(this).closest('form').find('input[name="quantity"]').trigger('change');
                });
            });
        })(jQuery);
    </script>
<?php
});