Add ability to get weather at <timestamp>

[alexanderdean]

We are interested in using WeatherAPI as the foundation of a weather-enrichment for Snowplow (snowplow/snowplow#456).

A showstopper requirement is the ability to get the weather at a specific timestamp. If we are (re-processing) 3 months of events from a mobile game, the current weather in a given location is a non-starter.

Would you be open to updating the API to support a provided timestamp? We would be happy to help integrate a provider that provides time-based weather.

[johnluetke]

Of course! Some details would need to be worked out about how to add that to provider selection, but I'm interested to see what you have in mind. Feel free to fork

[alexanderdean]

Awesome, we will have a go at this.