sensorcommands: add cstring header

Signed-off-by: Patrick Venture <venture@google.com>
Change-Id: Ie86be5e3b68f98a3690cb7b2ec9669a605d8d235
diff --git a/src/sensorcommands.cpp b/src/sensorcommands.cpp
index 7fc11a0..ce94d5a 100644
--- a/src/sensorcommands.cpp
+++ b/src/sensorcommands.cpp
@@ -19,6 +19,7 @@
 #include <chrono>
 #include <cmath>
 #include <commandutils.hpp>
+#include <cstring>
 #include <iostream>
 #include <ipmi_to_redfish_hooks.hpp>
 #include <ipmid/api.hpp>