Add support for extension APIService definition updates

[adammw]

Add support for extension APIService definition updates via the cert-controller library.

The APIService definition points to a service and caBundle like the existing webhook types, and extends the kubernetes API server using the aggregation layer to provide access to alternate apiGroups via that server.

There were no tests for other types of WebhookInfo apart from the Validating type - however I can work on adding some if required.

[adammw]

cc @mmirecki @adrianludwin @ritazh for visibility/review

[maxsmythe]

Thanks for the PR! Code LGTM.

If you are willing to add the tests, it would definitely be helpful.

[mmirecki]

/lgtm

[adammw]

Adding tests for the other webhook types in #37, will rebase onto that once merged.

[ritazh]

Thanks for the PR @adammw!
PR LGTM
Pending testings rebase from #37

[sozercan]

lgtm

[maxsmythe]

#37 merged

[ritazh]

@adammw now that #37 has been merged, please address the merge conflict and add tests for APIService.

[codecov-commenter]

Codecov Report

Merging #36 (ce78882) into master (cd3703c) will increase coverage by 0.29%.
The diff coverage is 45.45%.

@@            Coverage Diff             @@
##           master      #36      +/-   ##
==========================================
+ Coverage   53.35%   53.64%   +0.29%     
==========================================
  Files           1        1              
  Lines         373      384      +11     
==========================================
+ Hits          199      206       +7     
- Misses        115      117       +2     
- Partials       59       61       +2     

Flag	Coverage Δ
unittests	53.64% <45.45%> (+0.29%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
pkg/rotator/rotator.go	53.64% <45.45%> (+0.29%)	⬆️

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[adammw]

Rebased and resolved conflicts. Tests require version bumps to latest (k8s libs -> 0.23, controller-runtime -> 0.11, go -> 1.17) otherwise it gets stuck in version dependency errors.

[maxsmythe]

LGTM

@ritazh @sozercan I'll leave it to you to merge if the rebase LGTY

[ritazh]

Thanks @adammw!

[sozercan]

This might causes issues with GK when we need to vendor if it requires controller-runtime 0.11.