PHP Fatal error

@marinmatosevic Hey Marin,

thank you for the nice plugin.
Maybe some issues with PHP 8.0.16?

Best regards Tobias

2022/03/13 01:46:23 [error] 8951#8951: *2787763 FastCGI sent in stderr: “PHP message: PHP Fatal error: Uncaught Error: Call to a member function get_shipping_packages() on null in /var/www/clients/client1/web52/web/wp-content/plugins/free-shipping-label/includes/class-fsl-helper.php:137
Stack trace:
#0 /var/www/clients/client1/web52/web/wp-content/plugins/free-shipping-label/public/class-fsl-public.php(315): Devnet_FSL_Helper::get_free_shipping_min_amount()
#1 /var/www/clients/client1/web52/web/wp-content/plugins/free-shipping-label/public/class-fsl-public.php(301): Devnet_FSL_Public->product_label_html()
#2 /var/www/clients/client1/web52/web/wp-includes/class-wp-hook.php(307): Devnet_FSL_Public->get_price_html()
#3 /var/www/clients/client1/web52/web/wp-includes/plugin.php(189): WP_Hook->apply_filters()
#4 /var/www/clients/client1/web52/web/wp-content/plugins/woocommerce/includes/abstracts/abstract-wc-product.php(1835): apply_filters()
#5 /var/www/clients/client1/web52/web/wp-content/plugins/woocommerce-germanized/includes/abstracts/abstract-wc-gzd-product.php(643): W” while reading response header from upstream, client: 207.46.13.166, server: , request: “GET /wp-json/wp/v2/pages/84438 HTTP/2.0”, upstream: “fastcgi://unix:/var/lib/php5-fpm/web52.sock:”, host: “”