Adding export in index.mustache

Author: rsachan8

generator/cybersource-javascript-template/index.mustache

@@ -98,6 +98,6 @@
   exports.LogConfiguration = require('./authentication/logging/LogConfiguration.js');
   exports.SensitiveDataTags = require('./authentication/logging/SensitiveDataTags.js');
   exports.SensitiveDataMasker = require('./authentication/logging/SensitiveDataMasker.js');
-
+  exports.ExternalLoggerWrapper = require('./authentication/logging/ExternalLoggerWrapper.js');
   return exports;<={{ }}=>
 }));