No way to specify image architecture for pull command

Hello. I'm trying to use lilipod as a lightweight container manager for running distrobox on Ubuntu Touch and SailfishOS (mobile Linux distros).

It generally works after few workarounds like a wrapper for missing `getsubids` (similar to #7) and fixing subuid ranges on host. However for images like `registry.opensuse.org/opensuse/tumbleweed:latest` there seems to be no way to specify the correct architecture to fetch, and it will default to incompatible `amd64` on `arm64` host.

I'm not very familiar with OCI tools syntax, so please mention if this can be workarounded like by specifying the arch in the URL.