Update eventing nightly (#1415)

bumping knative.dev/eventing 08b0813...bff65d2:
  > bff65d2 Triggering long running background jobs when events occurs (# 7954)
  > 3ee2400 fix: sequence updates subscription where possible, instead of recreating it (# 7948)
  > 96e0f09 Bump rekt to main (# 7958)
  > e3604b8 [main] Upgrade to latest dependencies (# 7957)

Signed-off-by: Knative Automation <[email protected]>