update 20% to all woocommerce product prices

function update_all_products() {
	$query = new WC_Product_Query( array(
	    'limit' => -1,
	) );

	$products = $query->get_products();
	foreach( $products as $product ){
		$product->set_regular_price( $product->get_regular_price() + ($product->get_regular_price() * 0.2) );
		$product->save();
	}
}