fix(dependencies): Added missing xmlbuilder2 dependency and relevant exports

ts/index.ts

@@ -3,6 +3,8 @@ import * as plugins from './smartxml.plugins.js';
 export class SmartXml {
   constructor() {}
 
+  public create = plugins.xmlbuilder2.create;
+
   public parseXmlToObject<T = any>(xmlStringArg: string): T {
     const parser = new plugins.fastXmlParser.XMLParser({
       preserveOrder: true,