This also fix the type used for RuncOptions.SystemCgroup, hence introducing
an API break.
Signed-off-by: Kenfe-Mickael Laventure <mickael.laventure@gmail.com>
When we generate protobufs, descriptors outlining all messages and
services are merged into a single file that can be used to identify
unexpected changes to the API that may affect stability. We follow a
similar process to Go's stability guarantees using the protobuf
descriptors to identify changes before they become a problem.
Please see README.md for details.
Signed-off-by: Stephen J Day <stephen.day@docker.com>