[gnome-nibbles/gnome-3-20] Fix license in preferences dialog

[Michael Catanzaro <mcatanzaro src gnome org>]

commit 59a99895346bd7514f7dc04715d0af8a86cf7df7
Author: Michael Catanzaro <mcatanzaro gnome org>
Date:   Wed Jul 27 23:55:45 2016 -0500

    Fix license in preferences dialog
    
    License is GPLv3+ in GNOME 3.20

 src/gnome-nibbles.vala |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/gnome-nibbles.vala b/src/gnome-nibbles.vala
index 0a3c368..ffcf526 100644
--- a/src/gnome-nibbles.vala
+++ b/src/gnome-nibbles.vala
@@ -1037,7 +1037,7 @@ public class Nibbles : Gtk.Application
                                "Copyright © 1999–2008 Sean MacIsaac, Ian Peters, Andreas Røsdal\n" +
                                "Copyright © 2009 Guillaume Beland\n" +
                                "Copyright © 2015 Iulian-Gabriel Radu",
-                               "license-type", Gtk.License.GPL_2_0,
+                               "license-type", Gtk.License.GPL_3_0,
                                "authors", authors,
                                "documenters", documenters,
                                "artists", artists,