versioning.php

<?php
// Get the theme version & make it a named constant
$theme_data = wp_get_theme();
define( 'THEME_VERSION', $theme_data->Version );

// Use it in your enqueues 
wp_enqueue_style(
	'style_name',
	get_stylesheet_directory_uri() . '/style.css',
	array(),
	THEME_VERSION
);