WooCommerce Free Gift Coupons 3.6.0

* Update: Tested against WooCommerce 5.6.0.
* Fix: Prevent syncing a free gift to itself.
* Fix: Stop validating coupon, let WooCommerce core handle all validation. Resolves issue of coupon not being valid when sync product is a variation.
* Fix: Check if gift is either product or variation. Resolves issue with syncing to variation.

* New: Sync quantity of free gift to more than one product at a time.
* New: Compatibility with All Products for Subscriptions, free gifts are not valid when user subscribes to cart.
* Update: Cart validation, throw notice of unconfigured variable gift *before* user attempts checkout.
* Fix: Border styles for Twenty Twenty One theme.
* Fix: More specific jQuery listeners to resolve conflicts with Flatsome's cart quickview.

* New: Templates added for gift variation selection in cart, easier customization.
* New: No-JS graceful degradation for gift variation selection.
* New: Auto scroll when gift variation edit section is opened scrolls to the gift variation input.
* Fix: UX audit, revision to cart edit layout, screen reader and accessibility enhancements.
* Update: Tested against WC 4.9.
* Update: Remove coupon code from cart if all gift items are removed, and type is ‘free gift’.
* Update: Hide product removed notice if coupon is automatically removed.