Add players.update event documentation

docs/events.md

@@ -53,6 +53,23 @@ join into it.
 | Yes     | Yes      | No
 
 ### Payloads
-Request Payload: `IGameJoinRequest`
+Request Payload: `LobbyJoinRequest`
 
-Response Payload: `IGameJoinResponse`
+Response Payload: `LobbyJoinResponse`
+
+---
+
+## `players.update`
+Tells the client that the player list has been updated. This event is broadcast
+when a new player joins the game, or when a player has updated their ship
+design.
+
+### Supported Event Types
+| Request | Response | Broadcasted
+| ------- | -------- | -----------
+| No      | Yes      | Yes
+
+### Payloads
+Request Payload: N/A
+
+Response Payload: `PlayerUpdateResponse`