kubelet: add sjenning to kubelet subdirectory owners files

[sjenning]

What type of PR is this?
/kind cleanup
/sig node
/priority backlog

What this PR does / why we need it:
In the spirit of reducing approver burden for top-level kubelet owners, this PR adds me to the OWNERS files for specific subdirectories within pkg/kubelet. These are directories I have contributed to.

Does this PR introduce a user-facing change?:

NONE

/assign @derekwaynecarr @dchen1107

[k8s-ci-robot]

@sjenning: Adding the "do-not-merge/release-note-label-needed" label because no release-note block was detected, please follow our release note process to remove it.

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/test-infra repository.

[sjenning]

/release-note-none

[derekwaynecarr]

I support this, but will defer to @dchen1107 to provide her input as well.

[sjenning]

@dchen1107 could I get your thoughts/approval on this? Thanks!

[dchen1107]

/lgtm
/approve

Seth, thanks!

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: dchen1107, sjenning

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:

• pkg/kubelet/cadvisor/OWNERS [dchen1107]
• pkg/kubelet/cm/OWNERS [dchen1107]
• pkg/kubelet/eviction/OWNERS [dchen1107]
• pkg/kubelet/images/OWNERS [dchen1107]
• pkg/kubelet/metrics/OWNERS [dchen1107]
• pkg/kubelet/preemption/OWNERS [dchen1107]

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

[sjenning]

/retest

[k8s-ci-robot]

@sjenning: The following test failed, say /retest to rerun them all:

Test name	Commit	Details	Rerun command
pull-kubernetes-e2e-gce-device-plugin-gpu	89dc2c6	link	/test pull-kubernetes-e2e-gce-device-plugin-gpu

Full PR test history. Your PR dashboard. Please help us cut down on flakes by linking to an open issue when you hit one in your PR.

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/test-infra repository. I understand the commands that are listed here.