WooCommerce: round up shipping prices

functions.php

<?php
// Paste everything below this line to your child-theme's functions.php file. 

// Rounds up all shipping rates by the $roundUpBy value. 
// After pasting this snippet, reset the WooCommerce shipping cache, e.g. add an item to the cart.
add_filter('woocommerce_package_rates', function ($rates, $package) {
    $roundUpBy = 5;
    foreach ($rates as $rate) {
        $rate->cost = ceil($rate->cost / $roundUpBy) * $roundUpBy;
    }
    return $rates;
}, 10, 2);