Adds Logstash breaking changes to Install Upgrade Guide

Author: lcawl

docs/en/install-upgrade/breaking.asciidoc

@@ -8,8 +8,8 @@ use and make the necessary changes so your code is compatible with {version}.
 ** <<beats-breaking-changes,Beats {version} breaking changes>>
 ** <<elasticsearch-breaking-changes,{es} {version} breaking changes>>
 ** {hadoop-ref}/breaking-changes.html[Elasticsearch Hadoop {version} breaking changes]
-** <<kibana-breaking-changes,Kibana {version} breaking changes>>
-** {logstash-ref}/breaking-changes.html[Logstash {version} breaking changes]
+** <<kibana-breaking-changes,{kib} {version} breaking changes>>
+** <<logstash-breaking-changes,{ls} {version} breaking changes>>
 
 [IMPORTANT]
 ===============================
@@ -77,3 +77,18 @@ the complete list, go to {kibana-ref}/breaking-changes.html[{kib} breaking chang
 
 include::{kib-repo-dir}/migration/migrate_8_0.asciidoc[tag=notable-breaking-changes]
 
+[[logstash-breaking-changes]]
+=== {ls} breaking changes
+[subs="attributes"]
+++++
+<titleabbrev>{ls}</titleabbrev>
+++++
+
+coming[8.0.0]
+
+This list summarizes the most important breaking changes in {ls} {version}. For
+the complete list, go to
+{logstash-ref}/breaking-changes.html[Logstash breaking changes].
+
+include::{ls-repo-dir}/static/breaking-changes.asciidoc[tag=notable-breaking-changes]
+

docs/en/install-upgrade/index.asciidoc

@@ -1,10 +1,11 @@
 [[elastic-stack]]
 = Installation and Upgrade Guide
 
+:apm-repo-dir:       {docdir}/../../../../apm-server/docs/guide
+:beats-repo-dir:     {docdir}/../../../../beats/libbeat/docs
 :es-repo-dir:        {docdir}/../../../../elasticsearch/docs
 :kib-repo-dir:       {docdir}/../../../../kibana/docs
-:beats-repo-dir:     {docdir}/../../../../beats/libbeat/docs
-:apm-repo-dir:       {docdir}/../../../../apm-server/docs/guide
+:ls-repo-dir:        {docdir}/../../../../logstash/docs
 
 include::{asciidoc-dir}/../../shared/attributes.asciidoc[]
 include::{es-repo-dir}/Versions.asciidoc[]