Same problem here. I’m not a pro, but if you have only one language in your shop, you can edit /wp-content/plugins/woocommerce-cart-tab/cart-tab.php -file. Just replace item and items:
echo '<span class="contents">' . sprintf( _n( '%d item', '%d items', intval( $woocommerce->cart->get_cart_contents_count() ), 'woocommerce-cart-tab' ), intval( $woocommerce->cart->get_cart_contents_count() ) ) . '</span>';
Just a quick fix ??