message: JSON-RPC spec: fixed the data type of event.sequence_number
  The `sequence_number` property of the transaction event object has been erroneously specified as string. Changed to unsigned int64.
  Closes:
diff: @@ -10,7 +10,7 @@ An event emitted during a transaction
  | Name | Type | Description |
  |---------------------|--------------------------|----------------------------------------------------------------|
  | key | string | Gobally unique identifier of event stream |
  -| sequence_number | string | Sequence number of the current event in the given even stream |
  +| sequence_number | unsigned int64 | Sequence number of the current event in the given even stream |
  | transaction_version | unsigned int64 | Version of the transaction that emitted this event |
  | data | [EventData](#event-data) | Typed event data object |
  