Read current weather information from openweathermap.org.
$ WEATHER_API_KEY=<api key for openweathermap.org> WEATHER_LOCATION=<location> cargo run
# e.g.
$ WEATHER_API_KEY=1234567890 WEATHER_LOCATION=Helsinki,FI cargo run
# or
$ WEATHER_API_KEY=1234567890 WEATHER_LOCATION=Helsinki cargo run