Support Woocommerce Brands - Brands loads in category while create rules

Ensure compatibility with Woocommerce Brands, loading brands in categories when creating rules.

function woo_discount_rules_accepted_taxonomy_for_category_method($taxonomy){
    $taxonomy[] = 'product_brand';
    return $taxonomy;
}

add_filter('woo_discount_rules_accepted_taxonomy_for_category', 'woo_discount_rules_accepted_taxonomy_for_category_method', 10);

function woo_discount_rules_load_additional_taxonomy_method($categories, $product_id){
    $brands = get_the_terms( $product_id, 'product_brand' );
    if(!empty($brands)){
        foreach ($brands as $brand){
            $categories[] = $brand->term_id;
        }
    }

    return $categories;
}
add_filter('woo_discount_rules_load_additional_taxonomy', 'woo_discount_rules_load_additional_taxonomy_method', 10, 2);