* [no ci] deps: update docker to 23.0.3
This PR brings our docker/docker dependency (which is hosted at github.com/moby/moby)
up to 23.0.3 (forward about 2 years). Refactored our use of docker/libnetwork to
reference the package in its new home, which is docker/docker/libnetwork (it is
no longer an independent repository). Some minor nearby test case cleanup as well.
* add cl
When we copy the system DNS to a task's `resolv.conf`, we should set
the permissions as world-readable so that unprivileged users within
the task can read it.
