feat(l10n): add Urdu language support

lib/app/modules/settings/views/settings_page_select_the_language_trailing.dart

@@ -58,6 +58,8 @@ class SettingsPageSelectTheLanguageTrailing extends StatelessWidget {
         return 'বাংলা';
       case SupportedLanguage.german:
         return 'German';
+      case SupportedLanguage.urdu:
+        return 'اردو';
       default:
         return '';
     }

lib/app/utils/language/sentence_manager.dart

@@ -5,6 +5,7 @@ import 'package:taskwarrior/app/utils/language/french_sentences.dart';
 import 'package:taskwarrior/app/utils/language/spanish_sentences.dart';
 import 'package:taskwarrior/app/utils/language/bengali_sentences.dart';
 import 'package:taskwarrior/app/utils/language/german_sentences.dart';
+import 'package:taskwarrior/app/utils/language/urdu_sentences.dart';
 import 'package:taskwarrior/app/utils/language/sentences.dart';
 import 'package:taskwarrior/app/utils/language/supported_language.dart';
 
@@ -27,6 +28,8 @@ class SentenceManager {
         return BengaliSentences();
       case SupportedLanguage.german:
         return GermanSentences();
+      case SupportedLanguage.urdu:
+        return UrduSentences();
       case SupportedLanguage.english:
       default:
         return EnglishSentences();

lib/app/utils/language/supported_language.dart

@@ -8,6 +8,7 @@ enum SupportedLanguage {
   spanish,
   bengali,
   german,
+  urdu,
 }
 
 extension SupportedLanguageExtension on SupportedLanguage {
@@ -27,6 +28,8 @@ extension SupportedLanguageExtension on SupportedLanguage {
         return 'bn';
       case SupportedLanguage.german:
         return 'de';
+      case SupportedLanguage.urdu:
+        return 'ur';
       default:
         return '';
     }
@@ -48,6 +51,8 @@ extension SupportedLanguageExtension on SupportedLanguage {
         return SupportedLanguage.bengali;
       case 'de':
         return SupportedLanguage.german;
+      case 'ur':
+        return SupportedLanguage.urdu;
       default:
         return null;
     }