* Feature - Define the "Google Product Category" at the "Product Category" level.
* Tweak - Improved performance of the Google Product Category field.
* Tweak - Enhanced responsive styles for the Google Product Category field.
* Tweak - Tested compatibility with WC 5.6.
* Fix - Exclude out-of-stock product variations when the catalog only includes in-stock products.
* Feature - Define a product catalog only with specific products.
* Tweak - Added a "Filter by" field to the product catalog form.
* Tweak - Simplified the product catalog form when filtering by product categories.
* Tweak - Tested compatibility up to WC 5.4.
* Fix - Fixed the selection of subcategories for the "Google Product Category" field in the catalog settings form.
* Dev - Replaced the usage of the library `select2.js` by `selectWoo.js`.
