Include Tabulator in protobuf readme

[google-oss-prow[bot]]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: chases2

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[sultan-duisenbay]

/retest

[sultan-duisenbay]

/retest

[michelle192837]

/retest

[google-oss-prow[bot]]

@chases2: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
test-testgrid-npm	01be35253c61f8bd9ad0f6498cabcd607752eb11	link	true	/test test-testgrid-npm

Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md). If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes/test-infra](https://github.com/kubernetes/test-infra/issues/new?title=Prow%20issue:) repository. I understand the commands that are listed [here](https://go.k8s.io/bot-commands).

[chases2]

/hold Blocking until #1203 deflakes this test

[chases2]

Closing in favor of #1204