update readme and example

packages/stream_chat_localizations/example/lib/add_new_lang.dart

@@ -456,6 +456,9 @@ class MyApp extends StatelessWidget {
           Locale('hi'),
           Locale('fr'),
           Locale('it'),
+          Locale('es'),
+          Locale('ja'),
+          Locale('ko'),
           // Add support for additional 'nn' locale
           Locale('nn'),
         ],

packages/stream_chat_localizations/example/lib/main.dart

@@ -73,6 +73,9 @@ class MyApp extends StatelessWidget {
           Locale('hi'),
           Locale('fr'),
           Locale('it'),
+          Locale('es'),
+          Locale('ja'),
+          Locale('ko'),
         ],
         // Add GlobalStreamChatLocalizations.delegates
         localizationsDelegates: GlobalStreamChatLocalizations.delegates,

packages/stream_chat_localizations/example/lib/override_lang.dart

@@ -98,6 +98,9 @@ class MyApp extends StatelessWidget {
           Locale('hi'),
           Locale('fr'),
           Locale('it'),
+          Locale('es'),
+          Locale('ja'),
+          Locale('ko'),
         ],
         // Add overridden "CustomStreamChatLocalizationsEn.delegate" along with
         // "GlobalStreamChatLocalizations.delegates"