Load fresh CSS file each time when that CSS file get modified. User will see the latest changes all time.
// Load fresh CSS file each time when that CSS file get modified (User will see the latest changes all time)
// Ref - https://developer.wordpress.org/reference/functions/wp_enqueue_style/#comment-2056
wp_enqueue_style('main-style', get_stylesheet_directory_uri() . '/assets/css/main.css', array(), filemtime(get_stylesheet_directory() . '/assets/css/main.css'), false);