[gnome-chess] Update my copyright year

[Michael Catanzaro <mcatanzaro src gnome org>]

commit 411b51d201a796eb712954aa7cb69c8697d620c9
Author: Michael Catanzaro <mcatanzaro igalia com>
Date:   Tue Apr 24 12:20:04 2018 -0500

    Update my copyright year
    
    Looks like I've made some change in every year

 src/gnome-chess.vala |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/gnome-chess.vala b/src/gnome-chess.vala
index 20070e6..c2716a8 100644
--- a/src/gnome-chess.vala
+++ b/src/gnome-chess.vala
@@ -66,7 +66,7 @@ public class ChessApplication : Gtk.Application
     private ChessEngine? opponent_engine = null;
     private int engine_timeout_counter = 10;
     private string copyrights = """Copyright © 2010–2013 Robert Ancell
-Copyright © 2013–2014 Michael Catanzaro
+Copyright © 2013–2018 Michael Catanzaro
 Copyright © 2015–2016 Sahil Sareen""";
 
     private const ActionEntry[] app_entries =