We want all kpod subcommands to use the formats code to output
formats like json. Altering kpod diff --json to kpod diff --format json
like the kpod images command.
Signed-off-by: baude <bbaude@redhat.com>
kpod diff reports on differences between two layers, specified as
layer IDs, containers, or images. In the case of containers or
images, kpod diff produces a diff for the top layer
Signed-off-by: Ryan Cole <rcyoalne@gmail.com>