KEP-859: promote command headers to stable

[soltysh]

• One-line PR description: promote command headers to stable

• Issue link: Include kubectl command metadata in http request headers #859

/assign @ardaguclu
for sig-cli review

/assign @deads2k
for PRR review

/hold
so it doesn't merge accidentally before I get both of the above reviews in

[deads2k]

it's an older feature. We might have done it differently if we were doing it today, but with this feature already on and no negative impact, this lgtm

/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: deads2k, soltysh

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• keps/prod-readiness/OWNERS [deads2k,soltysh]
• keps/sig-cli/OWNERS [soltysh]

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[ardaguclu]

/lgtm
from sig-cli POV

[soltysh]

/hold cancel