Fix missing parameter in example (#1172)

Co-authored-by: Joe Spencer <js.developer.undefined@gmail.com>

Readme.md

@@ -127,7 +127,7 @@ GitHub issues have been disabled to focus on pull requests. ([#731](https://gith
  var url = 'http://example.com/wsdl?wsdl';
  var args = {name: 'value'};
 
- soap.createClient(url, function(err, client) {
+ soap.createClient(url, {}, function(err, client) {
  client.MyFunction(args, function(err, result) {
  console.log(result);
  });