update TRANSLATORS (#4406)

options/locale/TRANSLATORS

@@ -56,6 +56,7 @@ Morten Sørensen <klim8d AT gmail DOT com>
 Muhammad Fawwaz Orabi <mfawwaz93 AT gmail DOT com>
 Nakao Takamasa <at.mattenn AT gmail DOT com>
 Natan Albuquerque <natanalbuquerque5 AT gmail DOT com>
+Niclas Kroon <niclas DOT kroon AT gmail DOT com>
 Odilon Junior <odilon DOT junior93 AT gmail DOT com>
 Pablo Saavedra <psaavedra AT igalia DOT com>
 Richard Bukovansky <richard DOT bukovansky @ gmail DOT com>