[Automated] Update backstage-plugins-eventing nightly (#159)

Update eventing nightly

bumping knative.dev/eventing 5fb693f...4a6e7d2:
  > 4a6e7d2 [main] Upgrade to latest dependencies (# 8444)

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

Author: knative-automation