Added 6.7.1 changelog

Author: ezimuel

CHANGELOG.md

@@ -1,3 +1,7 @@
+## Release 6.7.1
+
+- Added `track_total_hits` in `search` endpoint [0c9ff47](https://github.com/elastic/elasticsearch-php/commit/9f4f0dfa331c4f50d2c88c0068afd3062e6ea353)
+
 ## Release 6.7.0
 
 - Removed requirement of `{type}` part in `indices.put_mapping`, see new API specification [here](https://github.com/elastic/elasticsearch/blob/v6.7.0/rest-api-spec/src/main/resources/rest-api-spec/api/indices.put_mapping.json)