Automatic merge from submit-queue
kubeadm: Make kube-proxy RollingUpgradeable
**What this PR does / why we need it**:
Sets the right updateStrategy for kube-proxy.
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #
Fixes: https://github.com/kubernetes/kubeadm/issues/319
**Special notes for your reviewer**:
**Release note**:
```release-note
NONE
```
@pipejakob @timothysc @kubernetes/sig-cluster-lifecycle-pr-reviews