Update net-istio nightly (#12555)
Update net-istio nightly (#12555)

bumping knative.dev/net-istio 3fc0d95...dc8f82e:
  > dc8f82e Update community files (# 854)

Signed-off-by: Knative Automation <f415700d4d0ce1c81810fe7553e3eea2bed16231@knative.team>
knative/serving,knative/serving