Change the minimal kustomize version in the developer guide

[tenzen-y]

What this PR does / why we need it:

We will change the minimal kubectl version in #1667. So, we should change the minimal kustomize version in the developer guide.

Ref:

• kubernetes v1.21 release note
• Katib: Add components guide website#2962 (comment)

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #

[aws-kf-ci-bot]

Hi @tenzen-y. Thanks for your PR.

I'm waiting for a kubeflow 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.

I understand the commands that are listed here.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[tenzen-y]

/assign

[andreyvelich]

Thank you for the update!
/ok-to-test
/lgtm
/approve

[google-oss-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: andreyvelich, tenzen-y

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [andreyvelich]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[anencore94]

From kubeflow/manifests repository's README, The required version of kustomize was v3.x, not v4.x.
And I guess the problem was not resolved yet following by this issue
Is it ok to upgrade the kustomize version in Katib though? @tenzen-y @andreyvelich

[tenzen-y]

Thank you for your comment! @anencore94

Previously, Katib could not be installed with kustomize v4.x. However, the problem has been resolved in #1498 and kubeflow/manifests#1840. So I believe there is no problem.

[anencore94]

Oh I see, Thank you for check :) @tenzen-y