/docs/registry-built-in describes docker hack for insecure registries, needs containerd hack too

[MatrixManAtYrService]

Recent versions of microk8s use containerd instead of docker. But the documenation at https://microk8s.io/docs/registry-private tells people to edit /etc/docker/daemon.json which has no effect.

Here's a few lines from my /var/snap/microk8s/current/args/containerd-template.toml. I added the last two so that I could reference private registry images in kubectl run commands from my laptop, even though microk8s is running on my desktop.

[plugins."io.containerd.grpc.v1.cri".registry.mirrors."localhost:32000"]
    endpoint = ["http://localhost:32000"]
[plugins."io.containerd.grpc.v1.cri".registry.mirrors."192.168.90.13:32000"]
    endpoint = ["http://192.168.90.13:32000"]

I learned about that file due to this issue: canonical/microk8s#390 but it seems like it should've been documented.

[MatrixManAtYrService]

Oh dear, this is already covered in the forum. Sorry for filing an issue in the wrong place.