WooCommerce Additional Variation Images 2.3.2

* Fix - Added the missing `woocommerce_single_product_image_thumbnail_html` hook.
* Fix - Fixed a conflict with "Default Variations" where multiple galleries could be loaded at once.
* Fix - Remove usage of jQuery catch.
* Fix - Support for Multiple Galleries if several are shown on the same page.
* Fix - Update node-sass to 4.14.1.

* Tweak - WC 5.0 compatibility.
* Tweak - WP 5.6 compatibility.

* Fix - Replace deprecated jQuery methods `.ready` and `.isFunction`