Add external 3 to fetched benficiaries

apps/ethereum_jsonrpc/lib/ethereum_jsonrpc/parity/fetched_beneficiaries.ex

@@ -172,6 +172,7 @@ defmodule EthereumJSONRPC.Parity.FetchedBeneficiaries do
   defp get_address_type(reward_type, index) when reward_type == "external" and index == 0, do: :validator
   defp get_address_type(reward_type, index) when reward_type == "external" and index == 1, do: :emission_funds
   defp get_address_type(reward_type, index) when reward_type == "external" and index == 2, do: :validator
+  defp get_address_type(reward_type, index) when reward_type == "external" and index == 3, do: :validator
   defp get_address_type(reward_type, _index) when reward_type == "block", do: :validator
   defp get_address_type(reward_type, _index) when reward_type == "uncle", do: :uncle
 end