Argo Event webhook authentication with Github

I'm trying to integrate the GitHub repo with the Argo Event Source webhook as an example (link). When the configured from the Github event returns an error.

'Invalid Authorization Header'.

Code:

apiVersion: argoproj.io/v1alpha1
kind: EventSource
metadata:
  name: ci-pipeline-webhook
spec:
  service:
    ports:
      - port: 12000
        targetPort: 12000
  webhook:
    start-pipeline:
      port: "12000"
      endpoint: /start-pipeline
      method: POST
      authSecret:
        name: my-webhook-token
        key: my-token