WooCommerce Product Vendors 2.2.8

* Add - Local development instructions and `wp-env` support.
* Dev - Update node version from 8.9.3 to 16.13.0.
* Dev - Update npm version from 5.5.1 to 8.0.0.
* Fix - Improve validation of Vendor store settings.
* Tweak - WC 7.1.0 compatibility.

* Declare support for HPOS.
* Dev - Add support for node 16 and npm 8.
* Fix - Compatibility issues with WooCommerce Deposits.
* Fix - Per product shipping rules import issue when a vendor is selected.
* Fix - Plugin assets now work via symlink.
* Fix - Vendors links use common permalink base.
* Tweak - Performance improvements for Bookings calendar and Bookings API.

* Fix - Ensure the orders page in the vendor dashboard is responsive.