Do we have sample for multi-container for ksvc

[vincent-pli]

Describe the change you'd like to see
I saw the multi-container features has been add to latest release v0.16.0: https://github.com/knative/serving/releases

Do we plan to add any sample or already has one? thanks.

Additional context
Add any other context or screenshots about the feature request here.

[nak3]

Hi @vincent-pli sorry for the delay. #2732 is trying to add the sample.

[abrennan89]

I believe this is fixed now by #2732 + #2787