[DOCS] Add 7.13.4 release notes (#1717) (#1718)

Author: jrodewig

docs/src/reference/asciidoc/appendix/release-notes/7.13.4.adoc

@@ -0,0 +1,7 @@
+[[eshadoop-7.13.4]]
+== Elasticsearch for Apache Hadoop version 7.13.4
+
+coming::[7.13.4]
+
+ES-Hadoop 7.13.4 is a version compatibility release, tested specifically against
+Elasticsearch 7.13.4.

docs/src/reference/asciidoc/appendix/release.adoc

@@ -9,6 +9,7 @@ This section summarizes the changes in each release.
 [[release-notes-7]]
 ===== 7.x
 
+* <<eshadoop-7.13.4>>
 * <<eshadoop-7.13.3>>
 * <<eshadoop-7.13.2>>
 * <<eshadoop-7.13.1>>
@@ -99,6 +100,7 @@ http://github.com/elastic/elasticsearch-hadoop/issues/XXX[#XXX]
 
 ////////////////////////
 
+include::release-notes/7.13.4.adoc[]
 include::release-notes/7.13.3.adoc[]
 include::release-notes/7.13.2.adoc[]
 include::release-notes/7.13.1.adoc[]