Bump to yangtools 0.6.1 and related versions
Bump to yangtools 0.6.1 and related versions

Change-Id: I9e56727c122e57ab6b0fc8e0273a4c10bad242a5
Signed-off-by: Robert Varga <b8bd3df785fdc0ff42dd1710c5d91998513c57ef@cisco.com>

bigdataops/bgpcep,opendaylight/bgpcep,bigdataops/bgpcep,inocybe/odl-bgpcep,inocybe/odl-bgpcep