Update CHANGELOG for 8.56.0

[ci skip]

CHANGELOG

 # Changelog for gitlab-workhorse
 
+## v8.56.0
+
+### Fixed
+- Return 413 HTTP status for S3 uploads if max upload limit is reached
+  https://gitlab.com/gitlab-org/gitlab-workhorse/-/merge_requests/655
+- Fix EXIF cleaning for S3 compatible Object Storage
+  https://gitlab.com/gitlab-org/gitlab-workhorse/-/merge_requests/
+
+### Other
+- Improve logging for image scaler
+  https://gitlab.com/gitlab-org/gitlab-workhorse/-/merge_requests/652
+- Update LabKit to v1.0.0
+  https://gitlab.com/gitlab-org/gitlab-workhorse/-/merge_requests/659
+
 ## v8.55.0
 
 ### Added

changelogs/unreleased/320-improve-image-scaler-logs.yml

----
-title: Improve logging for image scaler
-merge_request: 652
-author:
-type: other

changelogs/unreleased/fix-exif-on-multipart-uploads.yml

----
-title: Fix EXIF cleaning for S3 compatible Object Storage
-merge_request:
-author:
-type: fixed

changelogs/unreleased/sh-return-413-for-s3-artifact-uploads.yml

----
-title: Return 413 HTTP status for S3 uploads if max upload limit is reached
-merge_request: 655
-author:
-type: fixed

changelogs/unreleased/vendor-v1-0-0.yml

----
-title: Update LabKit to v1.0.0
-merge_request: 659
-author:
-type: other