serialization: add cereal support for maps

xyz.openbmc_project.Inventory.Decorator.ManufacturingExt added a 'dict'
type, so we need to add the corresponding cereal header.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I6d372298f2c942065d0f143d0e9c4bb0e1f226a6
diff --git a/gen_serialization.mako.hpp b/gen_serialization.mako.hpp
index df49740..f441670 100644
--- a/gen_serialization.mako.hpp
+++ b/gen_serialization.mako.hpp
@@ -5,6 +5,7 @@
 #include <cereal/types/string.hpp>
 #include <cereal/types/tuple.hpp>
 #include <cereal/types/vector.hpp>
+#include <cereal/types/map.hpp>
 #include "config.h"
 % for iface in interfaces:
 #include <${iface.header()}>