Update CHANGELOG.md

Author: turt2live

CHANGELOG.md

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 Changes in [1.11.4](https://github.com/vector-im/element-web/releases/tag/v1.11.4) (2022-08-31)
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+## 🔒 Security
+* Fixes for [CVE-2022-36059](https://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=CVE%2D2022%2D36059) and [CVE-2022-36060](https://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=CVE%2D2022%2D36060)
+
+Learn more about what we've been up to at https://element.io/blog/element-web-desktop-1-11-4-a-security-update-deferred-dms-and-more/
+Find more details of the vulnerabilities at https://matrix.org/blog/2022/08/31/security-releases-matrix-js-sdk-19-4-0-and-matrix-react-sdk-3-53-0
+
 ## ✨ Features
  * Device manager - scroll to filtered list from security recommendations ([\#9227](https://github.com/matrix-org/matrix-react-sdk/pull/9227)). Contributed by @kerryarchibald.
  * Device manager - updated dropdown style in filtered device list ([\#9226](https://github.com/matrix-org/matrix-react-sdk/pull/9226)). Contributed by @kerryarchibald.