Etcd Upgrade

[davidmccormick]

Remove support for Etcd v2
Bump default version to v3.2.26 (important bug fixes)

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by:
To fully approve this pull request, please assign additional approvers.
We suggest the following additional approver: c-knowles

If they are not already assigned, you can assign the PR to them by writing /assign @c-knowles in a comment when ready.

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[codecov-io]

Codecov Report

Merging #1605 into master will decrease coverage by 0.03%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master    #1605      +/-   ##
==========================================
- Coverage   25.49%   25.45%   -0.04%     
==========================================
  Files          97       97              
  Lines        5060     5040      -20     
==========================================
- Hits         1290     1283       -7     
+ Misses       3625     3613      -12     
+ Partials      145      144       -1

Impacted Files	Coverage Δ
pkg/api/etcd_cluster.go	26.31% <ø> (ø)	⬆️
pkg/api/cluster.go	0% <0%> (ø)	⬆️
pkg/api/etcd.go	31.32% <0%> (-2.7%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 00746e2...fc29a9f. Read the comment docs.