cmd/kubeadm: Replace deprecated func usage from the k8s.io/utils/pointer pkg

[ialidzhikov]

What type of PR is this?

/kind cleanup

What this PR does / why we need it:

See #111585 and #111585 (comment).

Does this PR introduce a user-facing change?

NONE

[k8s-ci-robot]

Please note that we're already in Test Freeze for the release-1.25 branch. This means every merged PR will be automatically fast-forwarded via the periodic ci-fast-forward job to the release branch of the upcoming v1.25.0 release.

Fast forwards are scheduled to happen every 6 hours, whereas the most recent run was: Sun Aug 14 07:34:40 UTC 2022.

[k8s-ci-robot]

Hi @ialidzhikov. Thanks for your PR.

I'm waiting for a kubernetes 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.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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[neolit123]

/lgtm
/approve

thanks

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: ialidzhikov, neolit123

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• cmd/kubeadm/OWNERS [neolit123]

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[neolit123]

/ok-to-test

[neolit123]

/triage accepted
/priority backlog

[neolit123]

/retest