Auto CSS version for child theme.

functions.php

<?php
/**
 * Enqueue scripts and styles.
 */
function fruit_scripts() {

	wp_dequeue_style( 'seed-style');
	wp_enqueue_style( 'fruit-css', get_stylesheet_directory_uri() . '/style.css', array(), filemtime( get_stylesheet_directory() . '/style.css' ) );
	wp_enqueue_script( 'fruit-js', get_stylesheet_directory_uri() . '/js/main.js', array(), '2017-1', true );

}
add_action( 'wp_enqueue_scripts', 'fruit_scripts' , 20 );