The background for this change:
1. Windows host-process containers do not have an OS version set
2. Buildx v0.10 started pushing manifest lists by default, but it never
has the OSVersion in the platform data (not that there is any way to
specify what particular OS version you want). The change means that
containerd cannot run images created with the new buildx on Windows
because there is no matching OSVersion in the list of manifests.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>