fix(backend): upgrade to gopkg.in/yaml.v3 to fix boolean support. Fixes #9451

[chensun]

Description of your changes:

Upgrade to gopkg.in/yaml.v3 to avoid converting string "y" to boolean "true".
Fixes #9451

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.

[chensun]

/hold

[chensun]

/unhold
/retest

[google-oss-prow]

@chensun: The following test 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-pipelines-samples-v2	20a877d	link	false	/test kubeflow-pipelines-samples-v2

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[Linchin]

Thank you @chensun!
/lgtm
/approve

[chensun]

/approve

[google-oss-prow]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: chensun, Linchin

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