Automatic merge from submit-queue (batch tested with PRs 42058, 41160, 42065, 42076, 39338)

Bump up dns-horizontal-autoscaler to 1.1.1

cluster-proportional-autoscaler 1.1.1 is releasing by kubernetes-incubator/cluster-proportional-autoscaler#26, also bump it up for dns-horizontal-autoscaler to introduce below features:
- Add PreventSinglePointFailure option in linear mode.
- Use protobufs for communication with apiserver.
- Support switching control mode on-the-fly.

Note:
The new entry `"preventSinglePointFailure":true` ensures kube-dns to have at least 2 replicas when there is more than one node. Mitigate the issue mentioned in #40063.

@bowei @thockin 

**Release note**:

```release-note
NONE
```