Automatic merge from submit-queue

Update kubectl to stable version for Addon Manager

Bumps up Addon Manager to v6.2, below images are pushed:
- gcr.io/google-containers/kube-addon-manager:v6.2
- gcr.io/google-containers/kube-addon-manager-amd64:v6.2
- gcr.io/google-containers/kube-addon-manager-arm:v6.2
- gcr.io/google-containers/kube-addon-manager-arm64:v6.2
- gcr.io/google-containers/kube-addon-manager-ppc64le:v6.2
- gcr.io/google-containers/kube-addon-manager-s390x:v6.2

@mikedanese 

cc @ixdy