Change logs:
- Change minimum replicas to zero in laddermode #111.
Images:
- k8s.gcr.io/cpa/cluster-proportional-autoscaler:1.8.5
- k8s.gcr.io/cpa/cluster-proportional-autoscaler-amd64:1.8.5
- k8s.gcr.io/cpa/cluster-proportional-autoscaler-arm:1.8.5
- k8s.gcr.io/cpa/cluster-proportional-autoscaler-arm64:1.8.5
- k8s.gcr.io/cpa/cluster-proportional-autoscaler-ppc64le:1.8.5