Fix Patchtester link in testing sample data

This change the Patchtester link in testing sample data

from: https://github.com/mbabker/patchtester/releases
to: https://github.com/joomla-extensions/patchtester/releases

ATM there is a forwarding but i think for consistency we should use the correct here.

### Question

Any update SQL needed? As this sample data should not us on prod sites.