YITH WooCommerce Gift Cards Premium 4.22.0

* New: support for WordPress 5.7
* New: support for WooCommerce 5.1
* New: added new shortcode to display the Gift this product form [yith_ywgc_display_gift_this_product_form]
* Update: YITH plugin framework
* Update: language files
* Fix: fixed the MM d, yy format in the gift card export
* Fix: added a condition to prevent errors when the product purchased as a gift has beeen deleted
* Dev: added new filter yith_ywgc_frontend_select2_load
* Dev: added a script in the export button to prevent the browser message
* Dev: changed the yith_wcgc_display_input_hidden_disable_gift_this_product hook priority
* Dev: add more conditions depending on the enabled features to the styles and scripts enqueue
* Dev: added new filter ywgc_gift_card_product_image_in_cart
* Dev: adding more security checks to the custom uploaded file

* New: support for WooCommerce 5.0
* Update: YITH plugin framework
* Update: language files
* Fix: pay the renew orders from YITH Subscriptions with the gift cards, if they have the enough balance to paid the full renew order
* Fix: fixed an error in the timezone for the postponed gift cards
* Fix: fixed the modal image selection
* Fix: fixed some non translatable strings
* Fix: don't display in my account gift cards without email
* Dev: added new filter ywgc_send_delayed_gift_cards_send_date
* Dev: added new filter ywgc_display_default_shipping_value_condition

* New: Support for WooCommerce 4.6
* Tweak: improves in the gift card table
* Update: updated spanish language
* Fix: fixed the image upload when no category is defined
* Fix: fixed the recalculate order when a gift card is applied
* Fix: fixed the issue with PayPal, when the gift card amount cover the product cost and part of the shipping
* Fix: fixed the coupons value when multiple gift cards as coupons are added
* Fix: fixed an issue with addons in gift card email
* Fix: fixed the sent date status
* Dev: moved order item meta before sending gift card email
* Dev: added the autoScriptToLang and autoLangToFont parametters to mpdf by default
* Dev: escaped preview strings