Cirrus CI will shut down June, 1st

[Tim Düsterhus]

Hi

FYI: Cirrus CI, which is used for FreeBSD, will shut down June, 1st: 
https://cirruslabs.org/

The use of Cirrus CI can likely be replaced by running a FreeBSD VM on 
GitHub Actions with https://github.com/marketplace/actions/freebsd-vm.

Best regards
Tim Düsterhus