Patch required for compiling with the latest commit of DD4hep

This patch is needed after a header cleanup in https://github.com/AIDASoft/DD4hep/pull/1432:

diff --git a/src/ONNXInference.cc b/src/ONNXInference.cc
index 7649182..09e9c4a 100644
--- a/src/ONNXInference.cc
+++ b/src/ONNXInference.cc
@@ -1,6 +1,7 @@
 #include "DDML/ONNXInference.h"

 #include <cassert>
+#include <iostream>

 #define DEBUGPRINT 0

simply because std::cout and std::endl are being used without the corresponding include, that was previously included through DD4hep.