Move runtime v2 proto

Move runtime v2 protos to api/runtime package.

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

Protobuild.toml

@@ -33,7 +33,11 @@ plugins = ["grpc", "fieldpath"]
 
 [[overrides]]
 # enable ttrpc and disable fieldpath and grpc for the shim
-prefixes = ["github.com/containerd/containerd/runtime/v1/shim/v1", "github.com/containerd/containerd/runtime/v2/task"]
+prefixes = [
+    "github.com/containerd/containerd/runtime/v1/shim/v1",
+    "github.com/containerd/containerd/api/runtime/task/v2",
+    "github.com/containerd/containerd/api/runtime/sandbox/v1",
+]
 plugins = ["ttrpc"]
 
 # Lock down runc config