Merge branch 'docs/add-link-to-gdk-elasticsearch' into 'master'

Doc: Add link to GDK guide on elasticsearch doc

See merge request gitlab-org/gitlab!61580

doc/integration/elasticsearch.md

@@ -108,6 +108,7 @@ The way you install the Go indexer depends on your version of GitLab:
 - For Omnibus GitLab 11.8 or greater, see [Omnibus GitLab](#omnibus-gitlab).
 - For installations from source or older versions of Omnibus GitLab,
   [install the indexer from source](#from-source).
+- If you are using GitLab Development Kit, see [GDK Elasticsearch how-to](https://gitlab.com/gitlab-org/gitlab-development-kit/-/blob/main/doc/howto/elasticsearch.md)
 
 ### Omnibus GitLab