Update swarmkit to 037b491. As swarmkit switched to a newer gRPC version, this also involves updating Docker's vendored gRPC, which in turn requires updating containerd to a new version that has protobufs generated against this gRPC version. Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com> Upstream-commit: 3e987e1732ee5c51e95934afabba3fedfd16c4af Component: engine