The csharp build needs to validate two axis

 - A variety of libvirt versions
 - A variety of csharp versions

We get coverage for both these axis by running a build against the
distro provided libvirt packages. All that is then missing is a build
against the latest libvirt git master, which only needs to be run on
a single distro, for which Fedora 32 is picked.

Latest Debian, Ubuntu, openSUSE and CentOS all stopped shipping the
monodevelop package, pointing people to flatpaks instead. Thus the
set of distros built is somewhat limited

Reviewed-by: Andrea Bolognani <abologna@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>