Testing changes for Jenkins CI (#863)

* testing

* more fixes

* downgrade docker-compose file version cause jenkins

* fixing matrix

* back to elasticsearch_version

* skip py3.7 for now there's a bug

* add build badge and remove 3.3
Sphinx doesn't play nice with 3.3

* sphinx 1.7 drops support for python 3.3

* updating test matrix

* remove travis

* updating badges

docker-compose.yml

@@ -1,10 +1,10 @@
-version: '3.3'
+version: '3.2'
 services:
   client:
     image: docker.elastic.co/clients/elasticsearch-py:${PYTHON_VERSION:-3}
     build:
       context: .
-      dockerfile: Dockerfile
+      dockerfile: ./Dockerfile
       args:
           PYTHON_VERSION: ${PYTHON_VERSION:-3}
     environment:
@@ -18,7 +18,7 @@ services:
       - elasticsearch
     command: ["true"]  # dummy command to override the command in the Dockerfile and do nothing.
   elasticsearch:
-    image: docker.elastic.co/elasticsearch/elasticsearch-oss:${ELASTIC_VERSION:-6.2.4}
+    image: docker.elastic.co/elasticsearch/elasticsearch-oss:${ELASTICSEARCH_VERSION:-6.2.4}
     volumes:
       - esvol:/tmp
     networks: