docs: Add chanelog entry

CHANGELOG.md

@@ -30,6 +30,7 @@ We use *breaking :warning:* to mark changes that are not backward compatible (re
 - [#3970](https://github.com/thanos-io/thanos/pull/3970) Azure: Adds more configuration options for Azure blob storage. This allows for pipeline and reader specific configuration. Implements HTTP transport configuration options. These options allows for more fine-grained control on timeouts and retries. Implements MSI authentication as second method of authentication via a service principal token.
 - [#4406](https://github.com/thanos-io/thanos/pull/4406) Tools: Add retention command for applying retention policy on the bucket.
 - [#4430](https://github.com/thanos-io/thanos/pull/4430) Compact: Add flag `downsample.concurrency` to specify the concurrency of downsampling blocks.
+- [#4438](https://github.com/thanos-io/thanos/pull/4438) Query: Added target metadata support.
 
 ### Fixed