Move runtime v2 proto

Move runtime v2 protos to api/runtime package.

Signed-off-by: Maksym Pavlenko <pavlenko.maksym@gmail.com>

runtime/v2/runc/pause/sandbox.go

@@ -26,8 +26,8 @@ import (
 	"github.com/containerd/ttrpc"
 	log "github.com/sirupsen/logrus"
 
+	api "github.com/containerd/containerd/api/runtime/sandbox/v1"
 	"github.com/containerd/containerd/plugin"
-	api "github.com/containerd/containerd/runtime/v2/task"
 )
 
 func init() {