[gnome-contacts] About: add Julian Sparber to the authors

[Niels De Graef <nielsdg src gnome org>]

commit f3fd0807c6e3bdf6dc3172bebd7aefab13a0ba16
Author: Julian Sparber <julian sparber net>
Date:   Thu Aug 29 10:20:04 2019 +0300

    About: add Julian Sparber to the authors

 src/contacts-app.vala | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/src/contacts-app.vala b/src/contacts-app.vala
index 4cab49e..180d83c 100644
--- a/src/contacts-app.vala
+++ b/src/contacts-app.vala
@@ -199,7 +199,8 @@ public class Contacts.App : Gtk.Application {
     string[] authors = {
       "Alexander Larsson <alexl redhat com>",
       "Erick Pérez Castellanos <erick red gmail com>",
-      "Niels De Graef <nielsdegraef gmail com>"
+      "Niels De Graef <nielsdegraef gmail com>",
+      "Julian Sparber <jsparber gnome org>"
     };
     string[] artists = {
       "Allan Day <allanpday gmail com>"