Update Changelog

Author: polyfractal

CHANGELOG.md

@@ -1,3 +1,11 @@
+## Release 5.4.0
+
+- fixed php 7.3 compatibility for elasticsearch 5 (#826) [[14a19ba]](http://github.com/elasticsearch/elasticsearch-php/commit/14a19ba)
+- Add `slices` param to whitelisted UBQ params (#752) [[13f248e]](http://github.com/elasticsearch/elasticsearch-php/commit/13f248e)
+- [DOCS] add link to community index helper (#681) (#726) [[6d414f2]](http://github.com/elasticsearch/elasticsearch-php/commit/6d414f2)
+- Fix issue with getting status of respository and snapshots. (#719) [[65aafc1]](http://github.com/elasticsearch/elasticsearch-php/commit/65aafc1)
+- fix DeleteByQuery param white list (#748) [[55e6a70]](http://github.com/elasticsearch/elasticsearch-php/commit/55e6a70)
+
 ## Release 5.3.2
 
 - Fix parsing of NodesInfo for Sniffing [[d771699]](http://github.com/elasticsearch/elasticsearch-php/commit/d771699)