include: add missing headers

Signed-off-by: Patrick Venture <venture@google.com>
Change-Id: I6b26a1bea2aae173b57dbd8affa0ba4991b1c9bb
diff --git a/include/PSUEvent.hpp b/include/PSUEvent.hpp
index 165ac92..e47670b 100644
--- a/include/PSUEvent.hpp
+++ b/include/PSUEvent.hpp
@@ -16,7 +16,12 @@
 
 #pragma once
 
+#include <boost/container/flat_map.hpp>
+#include <memory>
 #include <sdbusplus/asio/object_server.hpp>
+#include <set>
+#include <string>
+#include <vector>
 
 class PSUSubEvent
 {