upgrade to latest dependencies (#53)

bumping knative.dev/client 935c2a5...e23b4d6:
  > e23b4d6 Update k8s dependencies to v0.20.7  (# 1344)
bumping knative.dev/serving c9cdc34...629598c:
  > 629598c Update net-kourier nightly (# 11546)
  > 4d5784b Update net-istio nightly (# 11545)
  > 003e133 upgrade to latest dependencies (# 11543)

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