Update 2.13.2 release notes

Change-Id: I9951a6f4dae62691484ada0a657d2e76b8e01012
diff --git a/releases/2.13.md b/releases/2.13.md
index 2269a2d..2a134c2 100644
--- a/releases/2.13.md
+++ b/releases/2.13.md
@@ -462,6 +462,9 @@
   A new `--delete-caches` option is added to allow force delete of all
   caches.
 
+* [Issue 4797](https://bugs.chromium.org/p/gerrit/issues/detail?id=4797):
+Fix internal server error in OAuth extension point when E-Mail is not set.
+
 * [Issue 4784](https://bugs.chromium.org/p/gerrit/issues/detail?id=4784):
 Allow to edit user name for OAuth providers that don't expose user names.