docs: remove deleted options

The heartbeat mechanism is no longer used, as the adapter uses the NUMSUB command to get the number of peers.

[skip ci]

Author: darrachequesne

README.md

@@ -140,8 +140,6 @@ io.listen(3000);
 | `readCount`         | The number of elements to fetch per XREAD call.                                                                       | `100`          |
 | `blockTimeInMs`     | The number of ms before the XREAD call times out.                                                                     | `5_000`        |
 | `sessionKeyPrefix`  | The prefix of the key used to store the Socket.IO session, when the connection state recovery feature is enabled.     | `sio:session:` |
-| `heartbeatInterval` | The number of ms between two heartbeats.                                                                              | `5_000`        |
-| `heartbeatTimeout`  | The number of ms without heartbeat before we consider a node down.                                                    | `10_000`       |
 | `onlyPlaintext`     | Whether the transmitted data contains only JSON-serializable objects without binary data (Buffer, ArrayBuffer, etc.). | `false`        |
 
 ## How it works