WooCommerce Google Product Feeds 11.0.19

* Change: Amend cache-blocking headers to no-store
* Change: Allow excluded catalogue visibilities to be modified via filter
* Change: Additional logging in debug mode
* Change: Tweaks to XML self reference headers for clearer support
* Fix: Resolve issue where exclude checkbox on variations was not generated correctly
* Fix: Category selection on feed manage page should not be available for review feeds
* Fix: Resolve issue where "No default" displayed in stead of "Use default" when creating products

* Fix: Availability fields didn't always allow "Use default" to be set
* Change: Updates to bundled libraries

* Fix: Database upgrades didn't always run when upgrading between versions
* Fix: Correct currency not always applied with recent versions of WooCommerce Multicurrency
* Change: Updates to bundled libraries
* Change: "Send item group ID" defaults on for new installs
* Change: Remove legacy update code