v3.0.0

• BREAKING: Node.js v8 or later is now required
• BREAKING: steamID arguments in event callbacks are now SteamID objects
  • tradeRequest
  • professorSpeksReceived
• BREAKING: Protobuf.js v6 is now being used
  • Properties in objects (e.g. registeredServers event and backpack objects) are no longer converted to camelCase (e.g. defIndex) and are now in their original snake_case (e.g. def_index)
• BREAKING: Dropped support for node-steam; now only node-steam-user v4.2.0 or later is supported
• steamID arguments to method calls (e.g. trade and deliverGift) can now be SteamID objects