alpha channel: Bump k8s version to 1.6.6
alpha channel: Bump k8s version to 1.6.6

BradErz/kops,faraazkhan/kops,pdh/kops,MadDogTechnology/kops,chrislovecnm/kops,kubernetes/kops,andrewsykim/kops,chrislovecnm/kops,gambol99/kops,mad01/kops,MadDogTechnology/kops,faraazkhan/kops,mad01/kops,aledbf/kops,blakebarnett/kops,gambol99/kops,gambol99/kops,BradErz/kops,mad01/kops,kubernetes/kops,reactiveops/kops,faraazkhan/kops,tsupertramp/kops,reactiveops/kops,robinpercy/kops,reactiveops/kops,blakebarnett/kops,tsupertramp/kops,tsupertramp/kops,BradErz/kops,aledbf/kops,aledbf/kops,andrewsykim/kops,reactiveops/kops,robinpercy/kops,kubernetes/kops,aledbf/kops,MadDogTechnology/kops,robinpercy/kops,andrewsykim/kops,chrislovecnm/kops,BradErz/kops,pdh/kops,blakebarnett/kops,gambol99/kops,blakebarnett/kops,chrislovecnm/kops,mad01/kops,justinsb/kops,andrewsykim/kops,justinsb/kops,robinpercy/kops,pdh/kops,justinsb/kops,pdh/kops,tsupertramp/kops,faraazkhan/kops,MadDogTechnology/kops