[release-4.7] OWNERS: add more core team members as approvers

[openshift-cherrypick-robot]

This is an automated cherry-pick of #4997

/assign jstuever

[openshift-ci]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by:
To complete the pull request process, please assign smarterclayton after the PR has been reviewed.
You can assign the PR to them by writing /assign @smarterclayton in a comment when ready.

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Needs approval from an approver in each of these files:

• OWNERS

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[jstuever]

/assign @sdodson

[openshift-ci]

@openshift-cherrypick-robot: The following tests failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Rerun command
ci/prow/e2e-ovirt	f2121fb	link	/test e2e-ovirt
ci/prow/e2e-libvirt	f2121fb	link	/test e2e-libvirt
ci/prow/e2e-openstack	f2121fb	link	/test e2e-openstack
ci/prow/e2e-crc	f2121fb	link	/test e2e-crc

Full PR test history. Your PR dashboard.

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