Allow sort_by to be set when searching for events

[dNitza]

Hello and thanks for the plugin!

I was working on adding an event search integration and noticed that the plugin currently doesn't allow sort_by to be set when making requests against the /events/search/endpoint, it just defaults to date.

It also seems that the allowed sorting options don't match up to what is now available (which is something that probably changed with Eventbrite's 3rd version of the API — https://www.eventbrite.com.au/developer/v3/endpoints/events/#ebapi-get-events-search)

I've opened up a PR as a suggestion of how I'd see this working, but since the allowed sorting options don't quite match, those might need to be updated too.

Anyway, thanks again for the work on this plugin, it's much appreciated.

[kwight]

@dNitza thanks for looking at this :) What state is it in? You mentioned that sorting options aren't lining up, is that still the case?.. A small note on first look, we'd also need sort_by to be in the example lists of args, like here (they also would go in each of the default themes' templates).

We won't likely be looking at this again until January, so take your time if still interested, and feel free to close if not. Thanks!