YITH Frontend Manager for WooCommerce Premium 1.37.0

* New: Support for WordPress 5.4
* New: Support for WooCommerce 4.0
* Update: plugin framework
* Fix: The Polygon style issue
* Fix: Vendor can't edit their profile with The Retailer theme
* Fix: Products table style in Twenty16 theme
* Fix: Unable to save the frontend manager main shortcode inside the shortcode Gutenberg block
* Dev: yith_wcfm_products_action_uri to filter action uri for products section
* Dev: yith_wcfm_live_chat_macro_action_uri to filter action uri for Live chat macro section

* New: Support for WooCommerce 3.9
* Update: Plugin framework
* Update: Italian language
* Fix: Layout issue for orders table on tablet and smartphone
* Fix: Issue with deprecated function update_woocommerce_term_meta

* Fix: Unable to flush rewrite rules in admin area