`build --push` pushes wrong image name

When doing a `devcontainer build --workspace-folder . --image-name my/image:tag --push` the wrong image (e.g. `vsc-devcontainer-839d9d58687bee078581a54501bbf0ec1d94e4e7a1e7d74dd0f0f02c09f29e0c-features`) is pushed instead. The name used seems to be the same as if you do not specify a `--image-name` at all.

The only workaround is to build the image without `--push` and push it "manually" after the invocation of `devcontainer build`. However this can't be used to build and push a multiarch image in buildx, as this needs to be pushed directly out of buildx.