WooCommerce Product Add-Ons 6.8.3

* Tweak - Important: The price of flat fee add-ons is no longer added to the per unit product price in the cart, but directly to the product total.
* Tweak - Important: The add-on prices in the cart are now displayed next to the selected add-on options, instead of the add-on name.
* Tweak - Important: The 'woocommerce_addons_add_price_to_name' filter is now deprecated. Use 'woocommerce_addons_add_product_price_to_value' or 'woocommerce_addons_add_cart_price_to_value' or 'woocommerce_addons_add_order_price_to_value' instead.
* Tweak - Important: Requires Product Bundles 6.20.0+ and Composite Products 8.9.0+.
* Tweak - The prices of flat fee add-ons are now prefixed with a '+' sign in the cart/order templates to indicate that these prices are not included in the per unit product price.
* Tweak - The prices of quantity/percentage based add-ons are now hidden by default in the cart/order templates, as they are already included in the per unit product prices. To reveal them, use the 'woocommerce_addons_add_cart_price_to_value' or 'woocommerce_addons_add_order_price_to_value' filter.
* Tweak - Added basic telemetry using Tracks.

* Fix - Fixed styling for dismissible admin notices.

* Fix - Important: Security improvements.
* New - Added admin notice to stores that use a PHP version earlier than 7.0.
* Tweak - Added a notice when addons cannot be saved due to a low 'max_input_vars' value.
* Tweak - Updated the logic that determines in which admin screens, Product Add-Ons styles/scripts are loaded.
* Tweak - Optimized the way global addons are saved.
* Fix - Fixed a fatal error triggered when dividing the addon price by a zero quantity.