changeOwner method
Implementation
Future<void> changeOwner(String privateKeyFrom, String didNewOwner) async {
var changeOwnerFunction = _contract.function('changeOwner');
var tx = Transaction.callContract(
contract: _contract,
function: changeOwnerFunction,
parameters: [_didToAddress(didNewOwner)]);
await web3Client.sendTransaction(EthPrivateKey.fromHex(privateKeyFrom), tx,
chainId: _chainId);
}