Add s390x and powerpc support to release-0.12 pipeline

[Deepali1999]

PR Description

Added s390x & power architecture to the pipeline build platforms, enabling multi-arch image builds for s390x for branch release-0.12.

What type of PR is this?

/kind feature

What this PR does / why we need it

This PR adds s390x & power to the multi-architecture build platforms in the Tekton pipeline definition (.tekton/kueue-0-12-pull-request.yaml & .tekton/kueue-0-12-push-request.yaml).
With this change, images will be built for linux/x86_64,linux/ppc64le and linux/s390x architectures, enabling support for s390x & power systems.

Note:

The Dockerfile.rhel already supports multi-arch builds using TARGETARCH and TARGETPLATFORM.
No changes were needed in the Dockerfile.
E2E tests have passed for s390x locally.

[openshift-ci]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: Deepali1999
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[openshift-ci]

Hi @Deepali1999. Thanks for your PR.

I'm waiting for a openshift 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.

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[kannon92]

/ok-to-test

[kannon92]

/ok-to-test

[openshift-ci]

@Deepali1999: all tests passed!

Full PR test history. Your PR dashboard.

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-sigs/prow repository. I understand the commands that are listed here.