Custom APIServer SANs

[dominicgunn]

Changes

• Adds the ability to define custom SANs to the APIServer. Internally we found this incredibly useful when trying to roll changes to CIDRs inside of the cluster.

[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 #1586 into master will increase coverage by 0.04%.
The diff coverage is 45.45%.

@@            Coverage Diff             @@
##           master    #1586      +/-   ##
==========================================
+ Coverage   25.86%   25.91%   +0.04%     
==========================================
  Files          98       98              
  Lines        5068     5067       -1     
==========================================
+ Hits         1311     1313       +2     
+ Misses       3610     3607       -3     
  Partials      147      147

Impacted Files	Coverage Δ
pkg/api/cluster.go	0% <ø> (ø)	⬆️
credential/generator.go	0% <0%> (ø)	⬆️
pkg/model/credentials.go	61.76% <100%> (+2.38%)	⬆️

---

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 04c9aa5...3c7cfe1. Read the comment docs.

[davidmccormick]

/lgtm

[davidmccormick]

Thanks, this looks useful! 🙏