Update README.md (#2564)
Update README.md (#2564)

Automatic merge from submit-queue.

Update README.md

Documenting https://github.com/istio/test-infra/pull/662
frankbu/istio,smawson/istio,smawson/istio,frankbu/istio,istio/istio,istio/istio,istio/istio,frankbu/istio,geeknoid/istio,istio/istio,smawson/istio,geeknoid/istio,istio/istio,frankbu/istio,frankbu/istio,geeknoid/istio,geeknoid/istio,smawson/istio,smawson/istio,geeknoid/istio,geeknoid/istio,smawson/istio,frankbu/istio