Fix PortNumber type to support controller-gen

[erikgb]

What type of PR is this?

/kind bug

What this PR does / why we need it:

This PR suggests a workaround for kubernetes-sigs/controller-tools#1269. There is an open PR to fix this issue, kubernetes-sigs/controller-tools#1270, but it appears like the required change is a bit controversial and will at least take some time to get available in a new release of controller-tools.

With the minor change in this PR, I am able to generate CRDs in my WIP PR to upgrade cert-manager to K8s 1.34. See cert-manager/cert-manager@a122dd6.

Which issue(s) this PR fixes:

Fixes #

Does this PR introduce a user-facing change?:

NONE

CC: @dprotaso @JoelSpeed

[youngnick]

From @JoelSpeed's comments on another PR, it seems like this fix may continue working even after the controller-tools PR is fixed? If so, this seems worth doing to me.

[erikgb]

Thanks Nick! My priority is to be able to bump cert-manager to K8s 1.34, and it seems we need this PR merged or a release of controller-tools containing a fix for the issue. Last resort is copy-modify of the gateway-api types reused in cert-manager API, which is something I'm trying to avoid. At least at this point.

[JoelSpeed]

/lgtm

Should work in the long term, provided clients are on Go 1.23 or higher. The go module here requires 1.24 so I think this is safe

[youngnick]

/approve

[k8s-ci-robot]

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This pull-request has been approved by: erikgb, youngnick

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