Replying to Users Last Conversation not currently supported

[thewheat]

The API allows replying to the last conversation of a user but AdminConversationReply.cs does not seem to expose ways to identify the user

Tested and possible identifiers are intercom_user_id, email and user_id (below shows using user_id)

[kmossco]

I'll be finishing the move to netStandard 2.0 this week, and then will focus on bringing feature parity to the /users endpoint. If anyone wants to give this a try it would be perfect. 👌