Can't create repository following documentation example with (`--type docker`)

Luet version:
luet version 0.35.2 (Build time: 2024-04-22 08:57:59 UTC)

CPU architecture, OS, and Version:
AMD64, inside a suse linux distrobox container (it may not be relevant)

Describe the bug
I try to run through the repository creation in https://luet.io/docs/concepts/overview/repositories/. Everything works as expected, but when I create-repo with the argument --type docker I get the following output:

INFO   Generating docker images for packages in /tmp/out
  ERROR    while building repository artifact index: while initializing repository generator: while pushing metadata file associated to the artifact: Failed generating metadata tree /tmp/out:foo-bar-0.1.metadata.yaml: while loading image: Failed loading image: invalid reference format
          : exit status 1

To Reproduce

mkdir package
cat <<EOF > package/build.yaml
image: busybox
steps:
- echo "foo" > /foo
EOF
cat <<EOF > package/definition.yaml
name: "foo"
version: "0.1"
category: "bar" # optional!
EOF
sudo luet build --all --destination $PWD/out/ --tree $PWD/package
sudo luet create-repo --name "test" --output $PWD/out --packages $PWD/out --tree $PWD/package --type docker

Expected behavior

I would expect the last command to run with no errors

Logs

here is the output by sudo luet create-repo --name "test" --output $PWD/out --packages $PWD/out --tree $PWD/package --type docker --debug:

 DEBUG   (config.go:#204:github.com/mudler/luet/cmd/util.initContext)  System rootfs: /
  DEBUG   (config.go:#205:github.com/mudler/luet/cmd/util.initContext)  Colors true
  DEBUG   (config.go:#206:github.com/mudler/luet/cmd/util.initContext)  Logging level info
  DEBUG   (config.go:#207:github.com/mudler/luet/cmd/util.initContext)  Debug mode true
 INFO   Generating docker images for packages in /tmp/out
  DEBUG   (repository_docker.go:#54:github.com/mudler/luet/pkg/installer.(*dockerRepositoryGenerator).Initialize.func1)  Skipping directories
  DEBUG   (repository_docker.go:#126:github.com/mudler/luet/pkg/installer.(*dockerRepositoryGenerator).pushFileFromArtifact)  Generating image /tmp/out:foo-bar-0.1.metadata.yaml
  DEBUG   (simpledocker.go:#76:github.com/mudler/luet/pkg/compiler/backend.(*SimpleDocker).LoadImage)  🐋  Loading image: /var/tmp/luet/tempimage4186696045
  ERROR    while building repository artifact index: while initializing repository generator: while pushing metadata file associated to the artifact: Failed generating metadata tree /tmp/out:foo-bar-0.1.metadata.yaml: while loading image: Failed loading image: invalid reference format
          : exit status 1

Additional context