update-remote.sh adding 'unknown/unknown' to architecture list

[grooverdan]

https://github.com/docker-library/repo-info/blob/master/repos/mariadb/remote/10-jammy.md#mariadb10-jammy

Platforms: 8

    linux; amd64
    unknown; unknown
    linux; arm64 variant v8
    unknown; unknown
    linux; ppc64le
    unknown; unknown
    linux; s390x
    unknown; unknown

[yosifkit]

We haven't really updated the repo-info scripts to account for the provenance+SBOM data added during the docker buildx build --provenance=mode=max --sbom=generator=docker/scout-sbom-indexer:1-doi ... (which are the items with unknown architecture and OS in the image index).

In case you want to explore what is in there: https://oci.dag.dev/?image=mariadb%3A10-jammy

[tianon]

https://github.com/moby/buildkit/blob/fdd6e7fb8c3609add649de7757aa69f6b245f40e/docs/attestations/attestation-storage.md is also a good link (buildkit documentation about the format/objects)