chore: Change command to apply manifests in the docs

[rimolive]

Description of your changes:
Solves #10664

Checklist:

• The title for your pull request (PR) should follow our title convention. Learn more about the pull request title convention used in this repository.

[google-oss-prow]

@rimolive: The following tests failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
kubeflow-pipeline-e2e-test	b30ca01	link	false	/test kubeflow-pipeline-e2e-test
kubeflow-pipeline-upgrade-test	b30ca01	link	false	/test kubeflow-pipeline-upgrade-test
kubeflow-pipelines-samples-v2	b30ca01	link	false	/test kubeflow-pipelines-samples-v2

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[hbelmiro]

/lgtm

[hbelmiro]

It seems like we should update the docs as well. But maybe we should wait for kubeflow/website#3737 to get merged first.

[google-oss-prow]

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