YITH WooCommerce Advanced Reviews Premium 1.37.0

* New: support for WooCommerce 5.3
* Update: YITH plugin framework
* Fix: total items count in reviews list table
* Dev: added actions: ywar_review_metabox_saved, ywar_metabox_before_author_info_fields, ywar_metabox_after_author_info_fields
* Dev: new filter ywar_filter_reviews_by_search_term_clause

* New: support for WordPress 5.7
* New: support for WooCommerce 5.1
* Update: YITH plugin framework
* Dev: improved the get_reviews_stats function
* Dev: added post type check at the moment of delete reviews in backend

* Fix: fixed a problem where the reviews are not displayed