chore(package): update mongoose to version 4.7.8
chore(package): update mongoose to version 4.7.8

https://greenkeeper.io/
ratecity/keystone,concoursbyappointment/keystoneRedux,ratecity/keystone,ONode/keystone,ONode/keystone,rafmsou/keystone,matthewstyers/keystone,Pop-Code/keystone,vokal/keystone,rafmsou/keystone,benkroeger/keystone,trentmillar/keystone,concoursbyappointment/keystoneRedux,danielmahon/keystone,trentmillar/keystone,matthewstyers/keystone,benkroeger/keystone,vokal/keystone,frontyard/keystone,frontyard/keystone,naustudio/keystone,danielmahon/keystone,naustudio/keystone,dryna/keystone-twoje-urodziny,trentmillar/keystone,danielmahon/keystone,andrewlinfoot/keystone,dryna/keystone-twoje-urodziny,vokal/keystone,benkroeger/keystone,andrewlinfoot/keystone,Pop-Code/keystone,naustudio/keystone,matthewstyers/keystone,frontyard/keystone,andrewlinfoot/keystone