change C++ version to check against

Author: varunagrawal

gtsam/base/std_optional_serialization.h

@@ -56,7 +56,7 @@ namespace std { template<> struct is_trivially_move_constructible<boost::seriali
 #endif
 
 
-#if __cplusplus < 201703L
+#if __cplusplus < 201103L
 // function specializations must be defined in the appropriate
 // namespace - boost::serialization
 namespace boost {