[DOCS] Add 7.17.9 release notes (#2063)

Author: jbaiera

docs/src/reference/asciidoc/appendix/release-notes/7.17.9.adoc

@@ -0,0 +1,5 @@
+[[eshadoop-7.17.9]]
+== Elasticsearch for Apache Hadoop version 7.17.9
+
+ES-Hadoop 7.17.9 is a version compatibility release, tested specifically against
+Elasticsearch 7.17.9.

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-7.17.9>>
 * <<eshadoop-7.17.8>>
 * <<eshadoop-7.17.7>>
 * <<eshadoop-7.17.6>>
@@ -121,6 +122,7 @@ http://github.com/elastic/elasticsearch-hadoop/issues/XXX[#XXX]
 
 ////////////////////////
 
+include::release-notes/7.17.9.adoc[]
 include::release-notes/7.17.8.adoc[]
 include::release-notes/7.17.7.adoc[]
 include::release-notes/7.17.6.adoc[]