Update reference model version to 0.31 draft

Include new submodule for serialization library.

Change-Id: I38cdea3ed8ea3968d1dc06c689dab248d21b14fd
Signed-off-by: Eric Kunze <eric.kunze@arm.com>
diff --git a/reference_model/src/main.cpp b/reference_model/src/main.cpp
index 2c75ce9..4dc31e1 100644
--- a/reference_model/src/main.cpp
+++ b/reference_model/src/main.cpp
@@ -26,9 +26,9 @@
 #include <nlohmann/json.hpp>
 
 #define MODEL_VERSION_MAJOR 0
-#define MODEL_VERSION_MINOR 30
+#define MODEL_VERSION_MINOR 31
 #define MODEL_VERSION_PATCH 0
-#define MODEL_VERSION_DRAFT false
+#define MODEL_VERSION_DRAFT true
 
 using namespace TosaReference;
 using namespace tosa;
diff --git a/thirdparty/serialization_lib b/thirdparty/serialization_lib
index 8fcef21..343d6a7 160000
--- a/thirdparty/serialization_lib
+++ b/thirdparty/serialization_lib
@@ -1 +1 @@
-Subproject commit 8fcef215fdbb6f6423fc96f0af40f1f4e248fffb
+Subproject commit 343d6a703c3a270a01102ec468b59ef2967b595e