Update CHANGELOG-EE.md for 13.2.4-ee

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CHANGELOG-EE.md

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+## 13.2.4 (2020-08-11)
+
+### Performance (1 change)
+
+- Preload all associations in Vulnerability GraphQL API. !38556
+
+
 ## 13.2.3 (2020-08-05)
 - No changes.

ee/changelogs/unreleased/233017-preload-associations-in-graphql-vulnerability-type.yml

----
-title: Preload all associations in Vulnerability GraphQL API
-merge_request: 38556
-author:
-type: performance