Replace use of deprecated C Standard library headers in C++ code.

Change-Id: I9fa6630c7e4bdb2897df34d417635d8c7d8253bc
Signed-off-by: Tyler Chatow <tchatow@gmail.com>
diff --git a/y2018/control_loops/superstructure/arm/graph.cc b/y2018/control_loops/superstructure/arm/graph.cc
index 54ec79d..ad6f982 100644
--- a/y2018/control_loops/superstructure/arm/graph.cc
+++ b/y2018/control_loops/superstructure/arm/graph.cc
@@ -1,7 +1,7 @@
 #include "y2018/control_loops/superstructure/arm/graph.h"
 
-#include <assert.h>
 #include <algorithm>
+#include <cassert>
 
 namespace y2018 {
 namespace control_loops {