How do you make a codecommit trigger for a lambda func?

I tried adding this to my serverless.yml, but no love. It’s not a codecommit trigger:

functions:
  ack:
    image:
      name: notify-on-commit
      command: handler.notify_slack
    events:
      - eventBridge:
          pattern:
            source:
              - aws.codecommit
            detail:
              eventSource:
                - arn:aws:codecommit:us-west-2:ACCOUNT_ID:MY_REPO

Any ideas how to do this?