SecretRef specifies the Secret containing the token used
to validate the payload authenticity. The Secret must contain a 'token'
key. For GCR receivers, the Secret must also contain an 'email' key
with the IAM service account email configured on the Pub/Sub push
subscription, and may optionally contain an 'audience' key with the
expected OIDC token audience.
name
string required
Name of the referent.