Update the artifact attestation format so as to follow the SLSA Provenance schema
Following the documentation here: https://docs.gitlab.com/ee/ci/runners/configure_runners.html#attestation-format, you can see that gitlab generates attestations where the predicate
key and metadata
/materials
key are all siblings in the same level in the json.
However, if you look at the SLSA Provenance schema (https://slsa.dev/provenance/v0.2#schema), you can see that the metadata
and materials
key is supposed to be inside the predicate
key.
Gitlab should update the attestation so as to follow the SLSA Provenance schema properly. The correct format should be predicate.metadata.other_stuff
and predicate.materials.other_stuff