WooCommerce Product Bundles 8.3.5

* Tweak - Replaced selectWoo with self-maintained flavor of select2.
* Tweak - Minor styling tweaks for WordPress 5.3.
* Tweak - Fix variable bundled item 'for' attribute.
* Fix - Parent product always included in bundled variation search results due to a bug in WooCommerce search.

* Fix - Added WordPress 5.3 and WooCommerce 3.8 support.
* Fix - Prevent bundled item stock data from being exported.

* Fix - Uglify css assets.