Fix: fix broken olm 0.27.0 digest channel entry (on 0.28.x branch)

[AObuchow]

What does this PR do?

When adding the 0.28.0 olm digest bundle, the channel entry for 0.27.0 was mistakenly entered as 0.27. instead of 0.27.0, causing opm validate to fail. This PR fixes the typo so that the 0.28.0 release can succeed.

What issues does this PR fix or reference?

n/a

Is it tested? How?

Run opm validate olm-catalog/release-digest/. No error output should be shown.

PR Checklist

• [ ] E2E tests pass (when PR is ready, comment /test v8-devworkspace-operator-e2e, v8-che-happy-path to trigger)
  • [ ] v8-devworkspace-operator-e2e: DevWorkspace e2e test
  • [ ] v8-che-happy-path: Happy path for verification integration with Che

[openshift-ci[bot]]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: AObuchow, dkwon17

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Needs approval from an approver in each of these files: - ~~[OWNERS](https://github.com/devfile/devworkspace-operator/blob/0.28.x/OWNERS)~~ [AObuchow,dkwon17] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment