oci_pull: handle OCI-format images

[alexeagle]

We should be able to pull an image that's published in OCI format, for example crane manifest quay.io/buildah/stable

Also it means we should handle more Media Types:

application/vnd.oci.image.index.v1+json
application/vnd.oci.image.manifest.v1+json

[alexeagle]

we should also add a test that our output matches e.g crane pull thesayyn/debian:oci ./pco --format=oci
for example the index.json file we produce needs the right media types.

[seh]

Does google/go-containerregistry#1586 having merged (addressing google/go-containerregistry#1579) help advance this pursuit? Do we need a release there in order to make use of the new crane registry serve subcommand?

[thesayyn]

We'll be cutting a new release for go-containerregistry and rules_oci this week. that'll fix this issue.

[seh]

We'll be cutting a new release for go-containerregistry and rules_oci this week.

That’s great news. Overcoming this gap leaves only bazelbuild/bazel@dfdf63a arriving in a Bazel release to get me back to where I once was with rules_docker. Oh, one more: @alexeagle’s stamping-related changes in #70.

[alexeagle]

Leaving this open, as the new handling of images with a crane toolchain doesn't work under bzlmod:

oci.pull(
    name = "buildah",
    tag = "latest",
    image = "quay.io/buildah/stable",
    reproducible = False,
)

->

ERROR: An error occurred during the fetch of repository 'rules_oci~0.3.8~oci~buildah':
   Traceback (most recent call last):
        File "/shared/cache/bazel/user_base/359b45a24cf55cc22380e941fe3bcf54/external/rules_oci~0.3.8/oci/pull.bzl", line 315, column 36, in _oci_pull_impl
                mf, mf_len = _download_manifest(rctx, rctx.attr.identifier, mf_file)
        File "/shared/cache/bazel/user_base/359b45a24cf55cc22380e941fe3bcf54/external/rules_oci~0.3.8/oci/pull.bzl", line 247, column 30, in _download_manifest
                result = rctx.execute([crane, "manifest", "{}{}{}".format(rctx.attr.image, tag_or_digest, identifier), "--platform=all"])
Error in execute: Unable to load package for @[unknown repo 'oci_crane_linux_amd64' requested from @rules_oci~0.3.8]//:crane: The repository '@[unknown repo 'oci_crane_linux_amd64' requested from @rules_oci~0.3.8]' could not be resolved: No repository visible as '@oci_crane_linux_amd64' from repository '@rules_oci~0.3.8'