version: bump to v1.0.0-rc2
version: bump to v1.0.0-rc2

Signed-off-by: Brandon Philips <74d2b51265fa19d338eb593a7555ec2b932e59c0@coreos.com>

opencontainers/image-spec,vbatts/oci-image-spec,vbatts/oci-image-spec,jonboulle/image-spec,mattspencer-arm/image-spec,jonboulle/image-spec,mattspencer-arm/image-spec,opencontainers/image-spec