WooCommerce PDF Vouchers - WordPress Plugin 4.9.9

* [*] Fix: Fixed the issue with downloading the voucher.

* [+] New: Improved compatibility with WPML.
* [*] Fix: Fixed an issue of voucher redeem notification email not sent if partial redeem not enabled.
* [*] Fix: Fixed JS conflict issue with WC Marketplace plugin.

* [+] New: Added a frontend support with Dokan multi vendor plugin.
* [+] New: Added option to display extra information on voucher details
page with edit rights.
* [+] New: Added Migration script code for update voucher start date for voucher
which are generated based on purchased option.
* [*] Fix: Fixed email attachment from other plugin not working on order refund.