Add apiVersion to the code example (#13)

* Add apiVersion to the code example

* set the apiVersion in code example

Co-Authored-By: Tomas Della Vedova <[email protected]>

Author: 2 people

README.md

@@ -58,7 +58,8 @@ Create a client instance
 var elasticsearch = require('elasticsearch');
 var client = new elasticsearch.Client({
   host: 'localhost:9200',
-  log: 'trace'
+  log: 'trace',
+  apiVersion: '7.2', // use the same version of your Elasticsearch instance
 });
 ```