Breaking changes

Please see the notes in the 1.15 release about the apiGroup changing from kops
to kops.k8s.io
A controller is now used to apply labels to nodes. If you are not using AWS,
GCE or OpenStack your (non-master) nodes may not have labels applied
correctly.

Significant changes

If upgrading from 1.11 or earlier, please see the notes in previous releases
about upgrading through kubernetes 1.12, with the etcd3 upgrade.
A new component runs on the master nodes now: kops-controller.
kops-controller currently labels nodes, but will likely perform additional
functionality in future releases.

If either a Kops 1.16 alpha release or a custom Kops build was used on a cluster,
a kops-controller Deployment may have been created that should get deleted.
Run kubectl -n kube-system delete deployment kops-controller after upgrading to Kops 1.16.0-beta.1 or later.
Kubernetes 1.9 users will need to enable the PodPriority feature gate. This is required for newer versions of Kops.

To enable the Pod priority feature, follow these steps:
```
kops edit cluster
# Add the following section
spec:
  kubelet:
    featureGates:
      PodPriority: "true"
```

The kops/v1alpha1 API is deprecated and will be removed in kops 1.18. Users of kops replace will need to supply v1alpha2 resources.

Fix Github download url for nodeup @adri,@justinsb #8468
GCS: Don't try to set ACLs if bucket-policy only is set @justinsb #8493
Alicloud: allow use RAM role for OSS client @bittopaz #8025
Cilium - Add missing Identity Allocation Mode to Operator Template @daviddyball #8445
Make it possible to enable Prometheus metrics for Cilium @olemarkus #8433
Update cilium to 1.6.6 @olemarkus #8484

Please see the release notes for the full list of changes.