YITH WooCommerce Uploads Premium 1.32.0

* Update: updating plugin FW
* Fix: fixing a possible issue with a new filter

* New: support to WordPress 5.0
* Update: plugin core to version 3.1.6
* Update: Italian language
* Dev: new filter 'ywau_src_pretty_photo_script'

* Update: plugin framework
* Update: plugin description
* Update: plugin links