Bug in About link

[gioagu]

Hi!

Tiny bug, at least in version 5.4.2 of the Importer/Exporter used in Ubuntu 22.04. When you are in the About menu and click on the link to

"Get in touch with us on http://github.com/3dcitydb"

Something goes wrong, as in the Importer/Exporter console there are errors. Same thing happens when you click on the urls of the Partners.