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

ts/smartxml.plugins.ts

@@ -1,5 +1,7 @@
 import * as fastXmlParser from 'fast-xml-parser';
+import * as xmlbuilder2 from 'xmlbuilder2';
 
 export {
-  fastXmlParser
+  fastXmlParser,
+  xmlbuilder2,
 };