README: Remove obsolete information
README: Remove obsolete information

We're no longer expecting libvirt-go contributions to come in
through libvir-list, and also we have a dedicated CONTRIBUTING
file now.

Signed-off-by: Andrea Bolognani <3ada0bee826c753786fdbba72243dfba997094cf@redhat.com>

libvirt/libvirt-go,libvirt/libvirt-go,libvirt/libvirt-go,libvirt/libvirt-go