missing target image architecture

[nikolaydubina]

right now image is build for same architecture as current host.

$ ./llama-stack/bin/llama stack build --template local --image-type docker --name llama-stack
$ docker image inspect llamastack-llama-stack | grep Architecture

        "Architecture": "arm64",

however, how can we specify different target architecture? if say we need linux/amd64?