This upstreams `Sort()` as originally implemented in containerd in
https://github.com/containerd/containerd/0886ceaea2470edc7339dfc5ebe0e3257ae84d06
From that commit:
> Fix reference ordering in CRI image store
>
> Currently image references end up being stored in a
> random order due to the way maps are iterated through
> in Go. This leads to inconsistent identifiers being
> resolved when a single reference is needed to identify
> an image and the ordering of the references is used for
> the selection.
>
> Sort references in a consistent and ranked manner,
> from higher information formats to lower.
>
> Note: A `name + tag` reference is considered higher
> information than a `name + digest` reference since a
> registry may be used to resolve the digest from a
> `name + tag` reference.
Co-Authored-by: Derek McGowan <derek@mcg.dev>
Co-Authored-by: Maksym Pavlenko <pavlenko.maksym@gmail.com>
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>