Update copyright year in about dialog

Also remove link to my website (there shouldn't be any third-party
links, imho).

briar-gtk/data/ui/about_dialog.ui.in

@@ -16,11 +16,11 @@
     <property name="type_hint">normal</property>
     <property name="program_name">Briar GTK</property>
     <property name="version">@VERSION@</property>
-    <property name="copyright" translatable="yes" context="Used in about dialog">Copyright © 2019-2020 The Briar Project</property>
+    <property name="copyright" translatable="yes" context="Used in about dialog">Copyright © 2019-2021 The Briar Project</property>
     <property name="comments" translatable="yes" context="Used in about dialog">A Briar client for GTK desktop and mobile devices</property>
     <property name="website">@PACKAGE_URL@</property>
     <property name="website_label" translatable="yes" context="Used in about dialog to get to website">Visit Briar GTK website</property>
-    <property name="authors">Nico Alt https://nico.dorfbrunnen.eu</property>
+    <property name="authors">Nico Alt</property>
     <property name="logo_icon_name">app.briar.gtk</property>
     <property name="license_type">agpl-3-0-only</property>
   </object>