ES version change to 6.6.1 (#1620)

Author: SosthenG

CHANGELOG.md

@@ -12,6 +12,7 @@ All notable changes to this project will be documented in this file based on the
 
 ### Improvements
 * Added `native_function_invocation` CS rule [#1606](https://github.com/ruflin/Elastica/pull/1606)
+* Elasticsearch test version changed from 6.5.2 to 6.6.1 [#1620](https://github.com/ruflin/Elastica/pull/1620)
 
 ### Deprecated
 

README.md

@@ -17,7 +17,7 @@ All library issues should go to the [issue tracker from github](https://github.c
 
 Compatibility
 -------------
-This release is compatible with all Elasticsearch 6.x releases. It was tested with version 6.5.2.
+This release is compatible with all Elasticsearch 6.x releases. It was tested with version 6.6.1.
 
 
 Contributing

env/elasticsearch/Dockerfile

@@ -1,5 +1,5 @@
 #https://www.docker.elastic.co/
-FROM docker.elastic.co/elasticsearch/elasticsearch:6.5.2
+FROM docker.elastic.co/elasticsearch/elasticsearch:6.6.1
 MAINTAINER Nicolas Ruflin <[email protected]>
 
 RUN /usr/share/elasticsearch/bin/elasticsearch-plugin install --batch ingest-attachment