Easy way to add versioning to WordPress assets using the file timestamp as a version

functions.php

<?php
// This function will add ?ver=XXXX at the end of the file
function AddTimestampToAssets( $assetURI ) {
    // Get the FULL Relative URL
    $relativeURL = getcwd() . '/' . ltrim( (str_replace( home_url(), '', $assetURI )), '/' );
    
    // Check if the $relativeURL contains "?ver=", if so remove it
    if ( strpos ($relativeURL, "?ver=") )
        $relativeURL = explode("?ver=", $relativeURL)[0];

	if ( $relativeURL ) {
        	// Get the timestamp using PHP native function
		$timestamp = filemtime( $relativeURL ); 
        	// Add ?ver= parameter with value to the URI
        	$assetURI = add_query_arg( 'ver', $timestamp, $assetURI );
        	// Return the final URL
		return esc_url( $assetURI );
	}
}

// This function is going to add two WP filters to pass all the files to the AddTimestampToAssets function
function LoadAssetsWithVersioning() {
    // CSS's
    add_filter( 'style_loader_src', 'AddTimestampToAssets' );
    // JS's
    add_filter( 'script_loader_src', 'AddTimestampToAssets' );
}
// Let's force WP to run LoadAssetsWithVersioning when initialazing the site
add_action('init', 'LoadAssetsWithVersioning');