packaging: debian/copyright updates
This brings the upstream Debian-style copyright notice on par with Debian official, and adds v11.0 new contributors.
This instance will be upgraded to Heptapod 1.5.0rc (GitLab 16.11.1) on 2024-05-02 at 15:00 UTC+2
This brings the upstream Debian-style copyright notice on par with Debian official, and adds v11.0 new contributors.