BUILDPLATFORM to build stage to enable cross compile

[kaovilai]

Signed-off-by: Tiger Kaovilai tkaovila@redhat.com

[openshift-ci[bot]]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: kaovilai, weshayutin

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](https://github.com/openshift/openshift-velero-plugin/blob/master/OWNERS)~~ [kaovilai] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment

[openshift-ci[bot]]

@kaovilai: all tests passed!

Full PR test history. Your PR dashboard.

Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md). If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes-sigs/prow](https://github.com/kubernetes-sigs/prow/issues/new?title=Prow%20issue:) repository. I understand the commands that are listed [here](https://go.k8s.io/bot-commands).

[kaovilai]

/cherry-pick oadp-1.4

[openshift-cherrypick-robot]

@kaovilai: new pull request created: #275

In response to [this](https://github.com/openshift/openshift-velero-plugin/pull/272#issuecomment-2289861627): >/cherry-pick oadp-1.4 Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md). If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes-sigs/prow](https://github.com/kubernetes-sigs/prow/issues/new?title=Prow%20issue:) repository.