[Fix] Missing property "apiGroup" error

[yafengio]

When I was running kubectl -f config/manifests/inferencepool-resources.yaml, I encountered an error：

error: error validating "https://github.com/kubernetes-sigs/gateway-api-inference-extension/raw/main/config/manifests/inferencepool-resources.yaml": error validating data: ValidationError(ClusterRoleBinding.roleRef): missing required field "apiGroup" in io.k8s.api.rbac.v1.RoleRef; if you choose to ignore these errors, turn validation off with --validate=false

K8s Version: v1.27.3

[linux-foundation-easycla]

• ✅login: maratrixx / (cb0b136)
• ✅login: maratrixx / (cb0b136, fa9052e)

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[k8s-ci-robot]

Hi @maratrixx. Thanks for your PR.

I'm waiting for a kubernetes-sigs member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[nirrozenbaum]

/ok-to-test

[ahg-g]

so is this defaulted to rbac.authorization.k8s.io on newer k8s versions?

[yafengio]

Yes, I tried to run it under k8s v1.33.1 and had the same error.

error: error validating "config/manifests/inferencepool-resources.yaml": error validating data: ValidationError(ClusterRoleBinding.roleRef): missing required field "apiGroup" in io.k8s.api.rbac.v1.RoleRef; if you choose to ignore these errors, turn validation off with --validate=false

Client Version: v1.23.10
Server Version: v1.33.1

---

When I upgraded kubectl to a higher version, I didn't find any error:

Client Version: v1.33.2
Server Version: v1.33.1

and

Client Version: v1.33.2
Server Version: v1.27.3

---

So, it should be caused by the low version of kubectl. To be as compatible as possible with lower versions, it is recommended to add default values.

[ahg-g]

/approve
/lgtm

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: ahg-g, maratrixx

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