doc: Add release note for RPC Whitelist
doc: Add release note for RPC Whitelist

Former-commit-id: a530ee487d0c15bc03461d3d4977c0b971bac8a2
syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin