We should add the `ExternalArtifact` as a source in `ArtifactGenerator` to integrate with 3rd-party source controllers as per [RFC-0012](https://github.com/fluxcd/flux2/blob/main/rfcs/0012-external-artifact/README.md). xref: https://github.com/fluxcd/flux2/issues/5504
We should add the
ExternalArtifactas a source inArtifactGeneratorto integrate with 3rd-party source controllers as per RFC-0012.xref: fluxcd/flux2#5504