Clean up Instrumentation reviewers

[ehashman]

What type of PR is this?

/kind cleanup

What this PR does / why we need it:

Removes inactive SIG Instrumentation reviewers, and ensures all approvers are also marked as reviewers.

Which issue(s) this PR fixes:

N/A

Special notes for your reviewer:

See kubernetes/org#2497

I am defining "inactive" as <50 contributions on devstats for the past year and does not attend regular SIG meetings.

/sig instrumentation
/cc @dashpole

Does this PR introduce a user-facing change?

NONE

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

[k8s-ci-robot]

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[dashpole]

/lgtm

[ehashman]

/assign @liggitt

[liggitt]

/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: ehashman, liggitt

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• OWNERS [liggitt]

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[fejta-bot]

/retest
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