[#521] *: use stdlib errors package

Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>

pkg/services/util/response/unary.go

@@ -2,9 +2,9 @@ package response
 
 import (
 	"context"
+	"fmt"
 
 	"github.com/nspcc-dev/neofs-node/pkg/services/util"
-	"github.com/pkg/errors"
 )
 
 // HandleUnaryRequest call passes request to handler, sets response meta header values and returns it.
@@ -12,7 +12,7 @@ func (s *Service) HandleUnaryRequest(ctx context.Context, req interface{}, handl
 	// process request
 	resp, err := handler(ctx, req)
 	if err != nil {
-		return nil, errors.Wrap(err, "could not handle request")
+		return nil, fmt.Errorf("could not handle request: %w", err)
 	}
 
 	setMeta(resp, s.cfg)