The Docker docs in multiple places describe passing an annotation at the
command line like "index,manifest:com.example.name=my-cool-image", and
say that this will result in the annotation being applied to both the
index and the manifest. It doesn't seem like this was actually
implemented, and instead it just results in an annotation key with
"index,manifest:" at the beginning being applied to the manifest.
This change splits the part of the key before the colon by comma, and
creates an annotation for each type/platform given, so the
implementation should now match the docs.
Signed-off-by: Eli Treuherz <et@arenko.group>