Add cloudbuild.yaml file

[mkumatag]

What this PR does / why we need it:

This PR is for creating the cloudbuild.yaml which contains the definition of how to build the image for this repo.

More information: https://github.com/kubernetes/test-infra/blob/c5f5b3155733140e6cbd83185862df85935c0f1c/config/jobs/image-pushing/README.md

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 #
Ref: #332

Specify your PR reviewers:

/cc @gyliu513 @jichenjc @xunpan

Special notes for your reviewer:

/area provider/ibmcloud

1. Please confirm that if this PR changes any image versions, then that's the sole change this PR makes.

Release note:

NONE

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: mkumatag

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 [mkumatag]

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

[gyliu513]

/lgtm