KEP-4193: update KEP for v1.32 release

[munnerz]

• One-line PR description: update KEP with details around GA and extra info on what's implemented.

• Issue link: https://github.com/kubernetes/enhancements/issues/4193

• Other comments:

[munnerz]

/assign @liggitt

[liggitt]

/lgtm /approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: liggitt, munnerz

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