Fix includes

Add missing includes after boost update.

Change-Id: I762032db1c2856cc54b2dd98378c72281450458b
Signed-off-by: Jason M. Bills <jason.m.bills@linux.intel.com>
diff --git a/include/u-boot-env-mgr.hpp b/include/u-boot-env-mgr.hpp
index d033b4d..4cd0370 100644
--- a/include/u-boot-env-mgr.hpp
+++ b/include/u-boot-env-mgr.hpp
@@ -16,6 +16,7 @@
 
 #pragma once
 
+#include <boost/asio/io_service.hpp>
 #include <sdbusplus/asio/object_server.hpp>
 
 static constexpr const char* uBootEnvMgrServiceName =