Remove unused header

Tested: Code compiles

Signed-off-by: Ed Tanous <edtanous@google.com>
Change-Id: Idd1426bf5455f66ec873ebdebe96eb06e1df1fc0
diff --git a/redfish-core/include/server_sent_events.hpp b/redfish-core/include/server_sent_events.hpp
index 7613d7b..dd3cd36 100644
--- a/redfish-core/include/server_sent_events.hpp
+++ b/redfish-core/include/server_sent_events.hpp
@@ -17,7 +17,6 @@
 #pragma once
 
 #include <boost/asio/strand.hpp>
-#include <boost/beast/core/span.hpp>
 #include <boost/beast/http/buffer_body.hpp>
 #include <boost/beast/http/message.hpp>
 #include <boost/beast/version.hpp>