Update create-cluster-kubeadm.md

[EmmEff]

Fixed typo

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[xiangpengzhao]

/lgtm
Thanks @EmmEff !

[heckj]

/lgtm

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[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: EmmEff, heckj, xiangpengzhao

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• docs/setup/independent/create-cluster-kubeadm.md [heckj]

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