Install Package in Podman Machine on macOS

I needed to install qemu-user-static on podman running on macOS to enable multiarch build of Docker images. Assuming you already have brew install podman and podman machine start, how do you install a package?

$ podman machine ssh
$ sudo su -
# rpm-ostree install --reboot --idempotent qemu-user-static

I used the --reboot flag because that's what the aforementioned blog post instructed, i.e. reboot the VM.