null additional_data parsed from notification

[unieagle]

killbill-adyen-plugin/src/main/java/org/killbill/billing/plugin/adyen/client/model/NotificationItem.java

Line 46 in e4fcf8e

this.additionalData = null;

Hi @pierre @sbrossie , do you know why we initially ignored the addtional_data? for some chargebacks, adyen put the real reason code only in this field.

[pierre]

Indeed, it looks like an (old) oversight. Do you have some bandwidth to work on a PR?