update .clang-format

Added the header inclusion order to the .clang-format file generated
these changes.

Change-Id: I4f51a20f469de431ee6a5ba78e3f4da39c980fab
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/src/sdevent/event.hpp b/src/sdevent/event.hpp
index e3d1b22..9ef5791 100644
--- a/src/sdevent/event.hpp
+++ b/src/sdevent/event.hpp
@@ -1,9 +1,10 @@
 #pragma once
 
+#include <systemd/sd-event.h>
+
 #include <chrono>
 #include <memory>
 #include <sdbusplus/bus.hpp>
-#include <systemd/sd-event.h>
 
 // TODO: openbmc/openbmc#1720 - add error handling for sd_event API failures