Add Ubuntu Mantic build target

Are mirroring GItHub PRs here?

Yes, just mirroring missing ones that is worth to be mentioned in a promoted release log. This is anyway manual work - copy & paste or selecting from existing tickets.

why

To align with a procedure of making a list of changes from a single point - Jira releases. In less time / efforts then alternative options (which are IMO worse) - having two procedures (nobody does besides me) for making a list of changes, drop Jira and use GitHub only. We can ignore them and / or assume people will just look commit history. Which is rarely the case. People are just lazy …

What is this issue ? Are mirroring GItHub PRs here? If so, why?