WooCommerce Product Add-Ons 6.8.3

* Fix - Resolved a fatal error caused by missing regular prices in the product object.
* Fix - Resolved incorrect subtotals in the single product page when a tax suffix was used.
* Tweak - Removed duplicate filters.

* Tweak - Important: Updated the 'addon-start' template and added the tax status data attribute.
* Fix - Fixed an issue that made tax suffixes show up in non-taxable products with add-ons.
* Fix - Fixed a PHP warning triggered by a duplication of the 'apply_filters_deprecated' call.
* Fix - Resolved an issue that prevented some of the selected checkbox from being added to the cart when ordering again.
* Fix - Resolved an issue that threw a validation error when renewing a subscription with required add-ons.

* Fix - Resolved a PHP warning triggered when adding a Bundle/Composite without any container-level add-ons to the block-based cart.