feat: add support for additional cosign media types

mentioned in commit e73e27bc

mentioned in issue #697 (closed)

mentioned in merge request gitlab-org/build/CNG!1040 (merged)

mentioned in merge request gitlab-com/gl-infra/k8s-workloads/gitlab-com!1825 (merged)

mentioned in merge request gitlab-com/gl-infra/k8s-workloads/gitlab-com!1826 (merged)

mentioned in merge request gitlab-org/charts/gitlab!2601 (closed)

mentioned in merge request omnibus-gitlab!6181 (merged)

mentioned in merge request gitlab-development-kit!2656 (merged)