Fix links to latest release in index.md

Change-Id: Ib936b5fdd367e7f7401ef0eeaf8466f58fa332d1
diff --git a/index.md b/index.md
index 2f9cecb..95b004b 100644
--- a/index.md
+++ b/index.md
@@ -92,6 +92,6 @@
 |||---|||
 
 [download]: /releases/2.13.md
-[git gc]: https://gerrit-documentation.storage.googleapis.com/Documentation/2.13.4/config-gerrit.html#gc
-[plugins]: https://gerrit-documentation.storage.googleapis.com/Documentation/2.13.4/config-plugins.html
+[git gc]: https://gerrit-documentation.storage.googleapis.com/Documentation/2.13.6/config-gerrit.html#gc
+[plugins]: https://gerrit-documentation.storage.googleapis.com/Documentation/2.13.6/config-plugins.html
 [replicate]: https://gerrit.googlesource.com/plugins/replication/+doc/master/src/main/resources/Documentation/config.md