Pontoon: Update Serbian (sr) localization of WebThings Gateway
Pontoon: Update Serbian (sr) localization of WebThings Gateway

Localization authors:
- Марко Костић (Marko Kostić) <marko.m.kostic@gmail.com>

moziot/gateway,mozilla-iot/gateway,moziot/gateway,mozilla-iot/gateway,moziot/gateway,mozilla-iot/gateway,mozilla-iot/gateway,mozilla-iot/gateway