v2.1.0

Breaking changes:

• The apikey and locations keys in config.json need to be moved to wunderground.apikey and wunderground.locations, see https://github.com/ebaauw/homebridge-ws#configuration;
• Delete (the cached homebridge-ws accessories from) ~/.homebridge/accessories/cachedAccessories;
• To keep history, the history files need to be renamed from ~/.homebridge/history_WS-location.json to ~/.homebridge/history_WS-WGlocation.json

Enhancements:

• Support OpenWeatherMap as alternative provider of weather data, now that Wunderground is discontinuing their API, see #3;
• Use time of last weather report (as reported by the provider) for Last Updated.

Bump versions:

• homebridge-lib v3.1.1.