Update grpcio-tools version for nanopb

Installing the old version fails with is a newer host compiler
(GCC 11.1.0) is used.

Signed-off-by: Imre Kis <imre.kis@arm.com>
Change-Id: I8fbd91c76c5280964a2cce7e03ac726a39faba98
diff --git a/external/nanopb/requirements.txt b/external/nanopb/requirements.txt
index 8121141..b0db5ff 100644
--- a/external/nanopb/requirements.txt
+++ b/external/nanopb/requirements.txt
@@ -1,9 +1,9 @@
 #-------------------------------------------------------------------------------
-# Copyright (c) 2020-2021, Arm Limited and Contributors. All rights reserved.
+# Copyright (c) 2020-2022, Arm Limited and Contributors. All rights reserved.
 #
 # SPDX-License-Identifier: BSD-3-Clause
 #
 #-------------------------------------------------------------------------------
 
 protobuf==3.15.2
-grpcio-tools==1.32.0
+grpcio-tools==1.43.0