Add Slovak translation

src-ui/src/app/services/settings.service.ts

@@ -272,6 +272,12 @@ export class SettingsService {
         englishName: 'Russian',
         dateInputFormat: 'dd.mm.yyyy',
       },
+      {
+        code: 'sk-sk',
+        name: $localize`Slovak`,
+        englishName: 'Slovak',
+        dateInputFormat: 'dd.mm.yyyy',
+      },
       {
         code: 'sl-si',
         name: $localize`Slovenian`,