* Add ArchLinux, Debian Bullseye and CentOS Stream 8 to CI. * Add Alpine to CI matrix as well.
* CI tests: add note to main.yml * improve
* Add Fedora 32 to CI; drop Fedora 30 which is soon EOL. * Docker only supports Fedora up to 31; fortunately the 31 package seems to work for 32 too. * Also skip for Fedora 32, as it apparently has a similar problem to Fedora 31. ci_complete