copyright and include guard

Framework/Utilities/SaveBoostHistogram.hpp

+/*
+ * (c) Copyright 2020 CORSIKA Project, corsika-project@lists.kit.edu
+ *
+ * This software is distributed under the terms of the GNU General Public
+ * Licence version 3 (GPL Version 3). See file LICENSE for a full version of
+ * the license.
+ */
+
 #include <corsika/third_party/cnpy/cnpy.hpp>
 
 #include <boost/histogram.hpp>
@@ -8,6 +16,8 @@
 #include <utility>
 #include <vector>
 
+#pragma once
+
 namespace corsika::utl {
   /**
    * This functions saves a boost::histogram into a numpy file. Only rather basic axis