Adds empty known issues page

Author: KOTungseth

docs/release-notes/known-issues.md

@@ -0,0 +1,9 @@
+---
+navigation_title: "Known issues"
+mapped_pages:
+  - https://www.elastic.co/guide/en/elasticsearch/reference/current/es-connectors-known-issues.html
+---
+
+# Elasticsearch known issues [elasticsearch-known-issues]
+Known issues are significant defects or limitations that may impact your implementation. These issues are actively being worked on and will be addressed in a future release. Review the Elasticsearch known issues to help you make informed decisions, such as upgrading to a new version.
+

docs/release-notes/toc.yml

@@ -1,4 +1,5 @@
 toc:
   - file: index.md
+  - file: known-issues.md
   - file: breaking-changes.md
   - file: deprecations.md