Update changelog

CHANGELOG.md

@@ -126,6 +126,7 @@
 - Updated AP Inbox, fixes #3332. ([f8931dc7](https://github.com/pixelfed/pixelfed/commit/f8931dc7))
 - Updated AdminReportController, add account delete button. ([563817a9](https://github.com/pixelfed/pixelfed/commit/563817a9))
 - Updated ApiV1Controller, added /api/v2/media endpoint, fixes #3405 ([f07cc14c](https://github.com/pixelfed/pixelfed/commit/f07cc14c))
+- Updated AP fanout, added Content-Type and User-Agent for activity delivery ([@noellabo](https://github.com/noellabo)) ([209c125](https://github.com/pixelfed/pixelfed/commit/209c125))
 -  ([](https://github.com/pixelfed/pixelfed/commit/))
 
 ## [v0.11.2 (2022-01-09)](https://github.com/pixelfed/pixelfed/compare/v0.11.1...v0.11.2)