fix label consistency

[skonto]

Backport of this.

[knative-prow-robot]

Welcome @skonto! It looks like this is your first PR to knative/eventing-contrib 🎉

[knative-prow-robot]

Hi @skonto. Thanks for your PR.

I'm waiting for a knative member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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[matzew]

/ok-to-test

[knative-prow-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: matzew, skonto

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Needs approval from an approver in each of these files: - ~~[kafka/OWNERS](https://github.com/knative/eventing-contrib/blob/release-0.18/kafka/OWNERS)~~ [matzew] - ~~[test/OWNERS](https://github.com/knative/eventing-contrib/blob/release-0.18/test/OWNERS)~~ [matzew] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment

[knative-metrics-robot]

The following is the coverage report on the affected files. Say /test pull-knative-eventing-contrib-go-coverage to re-run this coverage report

File	Old Coverage	New Coverage	Delta
kafka/source/pkg/reconciler/source/resources/labels.go	Do not exist	100.0%