📖 update clusterctl provider contract for clusterclass support

[ykakarap]

What this PR does / why we need it:

This PR update the clusterctl provider contract for providers to opt into cluster class support.

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #

[sbueringer]

A few nits, but sounds good in general

[fabriziopandini]

A couple of nits from my side
Q: should we update also documentation in https://cluster-api.sigs.k8s.io/clusterctl/commands/generate-cluster.html

[fabriziopandini]

lgtm pending addressing open comments

[fabriziopandini]

/lgtm

[ykakarap]

The error in the "Broken Links" pipeline seems to be

ERROR: 1 dead links found!
[✖] #833 → Status: 0

This link is in the "Cluster Provider Spec and Status as CRDs" proposal doc and I believe the error is not related to changes in the current PR.

[fabriziopandini]

If I'm not wrong the link is correct, might be a flake...

[sbueringer]

/lgtm
Yeah looks correct. You can try a re-run by commit --amend + push --force

[ykakarap]

Yeah looks correct. You can try a re-run by commit --amend + push --force

I wonder if this will remove the lgtm label.
I believe someone with rights can just re-trigger the github workflow test form the UI.

[sbueringer]

Yeah looks correct. You can try a re-run by commit --amend + push --force

I wonder if this will remove the lgtm label. I believe someone with rights can just re-trigger the github workflow test form the UI.

Yup, it will remove them. Just suggested it because getting lgtm again shouldn't be a problem :)

I think someone with write or admin access to the repo should be able to restart the workflow.

[ykakarap]

@sbueringer can you please LGTM again 🙏🏼
Hopefull the test doesn't flake this time :)

[sbueringer]

Sure :)

/lgtm

[killianmuldoon]

/lgtm

[fabriziopandini]

/lgtm
/approve

@ykakarap please give a PSA in the office hours about this documentation being available

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

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