[Libguestfs] Few updates

Hi, Just few updates that I've given on IRC: For Fedora, since release 33+, the latest DNF update in the kickstart as been commented out. I've tried to add into the kickstart `repo --name=updates` and it looks like the resulting image works and is up to date. For Ubuntu, following https://github.com/rwmjones/guestfs-tools/issues/1, I've used `debian.preseed` partitioning part for Ubuntu and it should solve the issue on the impossibility of resizing the base image. For openSUSE, I've succeeded to revive Leap and notably version 15.2 works great. I hope to be able to send patches soon. Best regards, Frédéric