Polylang for WooCommerce 2.1

* Requires WordPress 5.7 or higher, WC 5.1 or higher, Polylang 3.0 or higher.
* Allow to translate cart when using multiple domains in recent browsers. Requires WC 6.7.
* Filter the product search block results by language.
* Add compatibility with Mix & Match Products 2.0. Props @helgatheviking
* Fix multiple emails sent to emails added through the filter 'woocommerce_email_recipient_new_order'
* Fix a deprecated notice with PHP 8.1
* Fix WooCommerce pages translations not created when using the WooCommerce wizard.
* Fix query for reserved stock
* Fix REST API for products with Polylang Pro 3.2+
* Fix deprecated notice in WooCommerce Subscriptions.
* Fix a fatal error with WooCommerce Variation Swatches and Photos.
* Fix WC Brands compatibility not loaded on frontend.
* Fix a conflict with Germanized for WooCommerce

* Fix error when manually sending the invoice email from backend.
* Fix a conflict with WooCommerce Germanized sending the new order email twice.

* Fix a conflict which could prevent emails from 3rd party plugins to be sent