Update kubeflow/training-operator manifests from v1.8.0

[rimolive]

Pull Request Template for Kubeflow manifests Issues

✏️ A brief description of the changes

As part of the Kubeflow 1.9 release, this PR bumps Training Operator manifests to v1.8.0

📦 List any dependencies that are required for this change

N/A

🐛 If this PR is related to an issue, please put the link to the issue here.

N/A

✅ Contributor checklist

• Make sure you have tested with kustomize. See Installation Prerequisites
• All the commits have been signed-off (To pass the DCO check)
• Submit the Contributor License Agreements (To pass the cla/google check)

---

You can join the CNCF Slack and access our meetings at the Kubeflow Community website. Our channel on the CNCF Slack is here #kubeflow-platform.

[rimolive]

/hold

cc @juliusvonkohout

[juliusvonkohout]

/lgtm
/approve

[google-oss-prow]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: juliusvonkohout

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 [juliusvonkohout]

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

[juliusvonkohout]

/unhold