The io/ioutil package has been deprecated as of Go 1.16, see
https://golang.org/doc/go1.16#ioutil. This commit replaces the existing
io/ioutil functions with their new definitions in io and os packages.
Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>
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.
Signed-off-by: Derek McGowan <derek@mcg.dev>
