Update Public Suffix List for Qt 5.15.15

We need to make sure all security critical 3rd party modules (https://wiki.qt.io/Third_Party_Code_in_Qt) are the latest one before we can release. Please update the latest version of Public suffix list

https://github.com/publicsuffix/list  

and its https://github.com/publicsuffix/list/blob/master/public_suffix_list.dat

Next release where this update is needed is Qt 5.15.15. This should be merged to tqtc/lts-5.15.15 by 31st of July so please provide  the update around 28th of July as this suffix list seems to be updated quite often.

Please Pick-to: 5.15. 5.15.15.