Add `Audience` field in `duckv1.Destination` about pkg

[creydr]

Sure, just assign the issue to you and go ahead.

[knative-prow]

@creydr:
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In response to this:

As the Eventing OIDC feature track describes, the Destination type allows to reference Addressable resources, raw Kubernetes services or absolute URLs. As for Addressables, it is necessary to additionally specify the required audience for those services.

Therefor the Destination type needs to allow to additionally specify the destinations Audience:

type Destination struct {

 ...

  // Audience is the OIDC audience. 
 // This need only be set, if the target is not an Addressable 
 // and thus the Audience can't be received from the Addressable itself.
 // In case the Addressable specifies an Audience too, the Destinations
 // Audience takes preference.
 // +optional
  Audience *string `json:"audience,omitempty"`
}

Additional context (optional)

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[abhijeetgauravm]

I would like to work on it!

[creydr]

Hi @abhijeetgauravm,
Glad to hear you want to contribute. I am currently creating the tasks for the OIDC implementation in Knative Eventing.
Just a side note: Not all of the created issues might contain all the needed information right now or might be reworked and need to be triaged (that's the reason why I marked them as DRAFT or added the kind/TBD label). But this issue looks fine I guess.

[abhijeetgauravm]

Can I fix it?