Fixes for runtimev2 and checkpoint restore

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

task.go

@@ -40,6 +40,7 @@ import (
 	"github.com/containerd/typeurl"
 	google_protobuf "github.com/gogo/protobuf/types"
 	digest "github.com/opencontainers/go-digest"
+	is "github.com/opencontainers/image-spec/specs-go"
 	"github.com/opencontainers/image-spec/specs-go/v1"
 	specs "github.com/opencontainers/runtime-spec/specs-go"
 	"github.com/pkg/errors"
@@ -424,6 +425,9 @@ func (t *task) Checkpoint(ctx context.Context, opts ...CheckpointTaskOpts) (Imag
 		return nil, err
 	}
 	index := v1.Index{
+		Versioned: is.Versioned{
+			SchemaVersion: 2,
+		},
 		Annotations: make(map[string]string),
 	}
 	if err := t.checkpointTask(ctx, &index, request); err != nil {