Automatic merge from submit-queue (batch tested with PRs 51039, 50512, 50546, 50965, 50467)
kubeadm: Get kube-dns based on the kubernetes version
**What this PR does / why we need it**:
Makes the kube-dns version used dependent on the kubernetes version. This is required for upgrades as we have to be able to handle one kube-dns version per branch for instance...
Currently a no-op though, as both v1.7 and v1.8 seem to use 1.14.4
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #
**Special notes for your reviewer**:
Dependency for https://github.com/kubernetes/kubernetes/pull/48899 (kubeadm upgrades)
**Release note**:
```release-note
NONE
```
@kubernetes/sig-cluster-lifecycle-pr-reviews
@kubernetes/dns-maintainers FYI; next time you bump DNS version, please update this func instead of the constant there...