human_sort_test: fix headers

IWYU. Use <> for dependency headers and "" for bmcweb headers.

Reference: https://gcc.gnu.org/onlinedocs/cpp/Search-Path.html

Tested: unit test passes.

Signed-off-by: Nan Zhou <nanzhoumails@gmail.com>
Change-Id: I6a329c8b04b0eccda7f601128f66770a7f119676
diff --git a/include/ut/human_sort_test.cpp b/include/ut/human_sort_test.cpp
index 7845f29..b9c245a 100644
--- a/include/ut/human_sort_test.cpp
+++ b/include/ut/human_sort_test.cpp
@@ -1,8 +1,10 @@
-#include <human_sort.hpp>
+#include "human_sort.hpp"
 
 #include <set>
+#include <string>
 
-#include "gmock/gmock.h"
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
 
 TEST(AlphaNum, NumberTests)
 {