How to provide a cosign public key for verification?

[ep4sh]

Question
Dear community,
could somebody guide me how to provide the cosign public key for image verification for cosign-gatekeeper-provider?
My public key is available with http schema. (http url file)

As I can see from the source code, the only available method is keyless:
https://github.com/sigstore/cosign-gatekeeper-provider/blob/main/provider.go#L85

But I might miss something, that's why gentle requesting for help.

Thank you,
Pasha.