Merge pull request #61198 from jpbetz/etcd-3.2-upgrade-reattempt

Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

Update default etcd server to 3.2 for kubernetes 1.11

Repply #59836 but with latest etcd 3.2 patch version (3.2.18 which includes mvcc fix and leader election timeout fix) and default `--snapshot-count` to 10k to resolve performance regression in previous etcd 3.2 server upgrade attempt (kubernetes/kubernetes#60589 (comment)).

See kubernetes/kubernetes#60589 (comment) for details on the root cause of the performance regression and scalability test results of setting `--snapshot-count` to 10k.

```release-note
Upgrade the default etcd server version to 3.2.18
```
@gyuho @shyamjvs @jdumars @timothysc

Kubernetes-commit: 9816b431886e356dfc96873392dd3ac66b5f0fe7

artifacts/example/rc.yaml

@@ -21,4 +21,4 @@ spec:
         imagePullPolicy: Never
         command: [ "/kube-sample-apiserver", "--etcd-servers=http://localhost:2379" ]
       - name: etcd
-        image: quay.io/coreos/etcd:v3.1.12
+        image: quay.io/coreos/etcd:v3.2.18