examples/Makefile.am: add missing file to dist

examples/Makefile.am

@@ -3,7 +3,7 @@
 # Copyright (C) 2011-2017                                Inria
 # Copyright (C) 2009-2019                                Université de Bordeaux
 # Copyright (C) 2017                                     Erwan Leria
-# Copyright (C) 2010-2015,2017,2018                      CNRS
+# Copyright (C) 2010-2015,2017,2018,2019                 CNRS
 # Copyright (C) 2011                                     Télécom-SudParis
 # Copyright (C) 2016                                     Uppsala University
 #