Update CHANGELOG for 8.53.0

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CHANGELOG

 # Changelog for gitlab-workhorse
 
+## v8.53.0
+
+### Added
+- Add route for Debian package uploads
+  https://gitlab.com/gitlab-org/gitlab-workhorse/-/merge_requests/610
+  Contributed by Mathieu Parent
+
+### Fixed
+- Don't log image scaler fail-overs as successes
+  https://gitlab.com/gitlab-org/gitlab-workhorse/-/merge_requests/636
+
+### Other
+- Exclude dot-files from "make fmt" target
+  https://gitlab.com/gitlab-org/gitlab-workhorse/-/merge_requests/641
+- Add max_processes Prometheus metric for image scaling
+  https://gitlab.com/gitlab-org/gitlab-workhorse/-/merge_requests/640
+- Simplify config handling in main()
+  https://gitlab.com/gitlab-org/gitlab-workhorse/-/merge_requests/634
+- Default MaxScalerProcs to num_cores / 2
+  https://gitlab.com/gitlab-org/gitlab-workhorse/-/merge_requests/635
+- Add a total requests metric for image scaling
+  https://gitlab.com/gitlab-org/gitlab-workhorse/-/merge_requests/638
+
 ## v8.52.0
 
 ### Fixed

changelogs/unreleased/311-dont-log-success-for-failovers.yml

----
-title: Don't log image scaler fail-overs as successes
-merge_request: 636
-author:
-type: fixed

changelogs/unreleased/debian_route.yml

----
-title: Add route for Debian package uploads
-merge_request: 610
-author: Mathieu Parent
-type: added

changelogs/unreleased/jv-config-struct.yml

----
-title: Simplify config handling in main()
-merge_request: 634
-author:
-type: other

changelogs/unreleased/mk-fmt-no-dot-files.yml

----
-title: Exclude dot-files from "make fmt" target
-merge_request: 641
-author:
-type: other

changelogs/unreleased/mk-image-scaler-max-procs-metric.yml

----
-title: Add max_processes Prometheus metric for image scaling
-merge_request: 640
-author:
-type: other

changelogs/unreleased/mk-image-scaler-total-requests-metric.yml

----
-title: Add a total requests metric for image scaling
-merge_request: 638
-author:
-type: other

changelogs/unreleased/mk-remove-image-scaler-defaults.yml

----
-title: Default MaxScalerProcs to num_cores / 2
-merge_request: 635
-author:
-type: other