reference that xhyve is now available via homebrew.
reference that xhyve is now available via homebrew.

Signed-off-by: António Meireles <9056f7c1f560fe4e0c75ab3cde8bee0cf3d504f4@reformi.st>

ecnahc515/coreos-xhyve,coreos/coreos-xhyve,AntonioMeireles/corectl,chancez/coreos-xhyve,AntonioMeireles/corectl,AntonioMeireles/coreos-xhyve,AntonioMeireles/coreos-xhyve,TheNewNormal/corectl,marineam/coreos-xhyve,TheNewNormal/corectl,jbergstroem/coreos-xhyve,tt/coreos-xhyve,myobie/coreos-xhyve