Minor refactoring of changelog

Signed-off-by: Kevin Hellemun <17928966+OGKevin@users.noreply.github.com>

CHANGELOG.md

@@ -10,14 +10,17 @@ NOTE: As semantic versioning states all 0.y.z releases can contain breaking chan
 We use *breaking :warning:* to mark changes that are not backward compatible (relates only to v0.y.z releases.)
 
 ## Unreleased
-- [#3259](https://github.com/thanos-io/thanos/pull/3259) Thanos BlockViewer: Added a button in the blockviewer that allows users to download the metadata of a block.
 
+### Added
+- [#3259](https://github.com/thanos-io/thanos/pull/3259) Thanos BlockViewer: Added a button in the blockviewer that allows users to download the metadata of a block.
 
 ### Fixed
-- [#3261](https://github.com/thanos-io/thanos/pull/3261) Thanos Store: Use segment files specified in meta.json file, if present. If not present, Store does the LIST operation as before.
 - [#3257](https://github.com/thanos-io/thanos/pull/3257) Ruler: Prevent Ruler from crashing when using default DNS to lookup hosts that results in "No such hosts" errors.
 - [#3276](https://github.com/thanos-io/thanos/pull/3276) Query Frontend: Support query splitting and retry for labels and series requests.
 
+### Changed
+- - [#3261](https://github.com/thanos-io/thanos/pull/3261) Thanos Store: Use segment files specified in meta.json file, if present. If not present, Store does the LIST operation as before.
+
 ### Fixed
 
 ## [#3257](https://github.com/thanos-io/thanos/pull/3257) Ruler: Prevent Ruler from crashing when using default DNS to lookup hosts that results in "No such hosts" errors.