Support for Elasticsearch 7.4 (#979)

* Update code generation (#969)

* Updated code generation scripts to use the new spec

* API generation

* Fix bad link

* Updated API reference doc (#945)

* Updated API reference doc

* Updated docs script

* Fix issue; node roles are defaulting to true when undefined (fal… (#967)

* Fix issue; nodeFilter was unable to filter because master, data, and ingest role were true if even they were false on the node.

* Test nodesToHost of BaseConnectionPool correctly maps node roles

* API generation

* Docker: use 7.4-SNAPSHOT

* API generation

* Use 7.4 stable

scripts/es-docker.sh

@@ -23,7 +23,7 @@ if [ "$1" == "--detach" ]; then
     --detach \
     --network=elastic \
     --name=elasticsearch \
-    docker.elastic.co/elasticsearch/elasticsearch:7.3.0
+    docker.elastic.co/elasticsearch/elasticsearch:7.4.0
 else
   exec docker run \
     --rm \
@@ -34,5 +34,5 @@ else
     -p 9200:9200 \
     --network=elastic \
     --name=elasticsearch \
-    docker.elastic.co/elasticsearch/elasticsearch:7.3.0
+    docker.elastic.co/elasticsearch/elasticsearch:7.4.0
 fi