Update copyright dates

README.adoc

@@ -82,7 +82,7 @@ Gitchart is used to build statistics for WeeChat: https://weechat.org/dev/stats/
 == Copyright
-Copyright (C) 2013-2017 Sébastien Helleu <flashcode@flashtux.org>
+Copyright (C) 2013-2018 Sébastien Helleu <flashcode@flashtux.org>
 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by

gitchart.py

 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
 #
-# Copyright (C) 2013-2017 Sébastien Helleu <flashcode@flashtux.org>
+# Copyright (C) 2013-2018 Sébastien Helleu <flashcode@flashtux.org>
 #
 # This file is part of gitchart.
 #

setup.py

 # -*- coding: utf-8 -*-
 #
-# Copyright (C) 2013-2017 Sébastien Helleu <flashcode@flashtux.org>
+# Copyright (C) 2013-2018 Sébastien Helleu <flashcode@flashtux.org>
 #
 # This file is part of gitchart.
 #