[gnome-todo] application: Update copyright date

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit 22f0e2dceeb7412070d40b4803c5718543d62bd5
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Mon May 11 21:29:28 2020 -0300

    application: Update copyright date

 src/gtd-application.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/gtd-application.c b/src/gtd-application.c
index 2a5233e..6e3170c 100644
--- a/src/gtd-application.c
+++ b/src/gtd-application.c
@@ -144,7 +144,7 @@ gtd_application_show_about (GSimpleAction *simple,
   gtk_show_about_dialog (GTK_WINDOW (self->window),
                          "program-name", program_name,
                          "version", GTD_VCS_TAG,
-                         "copyright", _("Copyright \xC2\xA9 2015–2018 The To Do authors"),
+                         "copyright", _("Copyright \xC2\xA9 2015–2020 The To Do authors"),
                          "license-type", GTK_LICENSE_GPL_3_0,
                          "authors", authors,
                          "artists", artists,