Update net-istio nightly (#13309)
Update net-istio nightly (#13309)

bumping knative.dev/net-istio 8505966...d9f370b:
  > d9f370b upgrade to latest dependencies (# 978)

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

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