docs: add changelog entry for #8762

Signed-off-by: Pavel Litvyak <pvlltvk@gmail.com>

Author: pvlltvk

CHANGELOG.md

@@ -18,6 +18,7 @@ It is recommend to upgrade the storage components first (Receive, Store, etc.) a
 - [#8714](https://github.com/thanos-io/thanos/pull/8714): Tracing: Fix `tls_config` fields (`ca_file`, `cert_file`, `key_file`) being silently ignored when using the OTLP gRPC exporter. Previously, deployments using a private CA or mTLS client certificates had to work around this via `OTEL_EXPORTER_OTLP_CERTIFICATE` and related environment variables.
 - [#8128](https://github.com/thanos-io/thanos/issues/8128): Query-Frontend: Fix panic in `AnalyzesMerge` caused by indexing the wrong slice variable, leading to an out-of-range access when merging more than two query analyses.
 - [#8720](https://github.com/thanos-io/thanos/issues/8720): Receive: Fix 503 errors during restarts in some cases.
+- [#8762](https://github.com/thanos-io/thanos/pull/8762): Query-Frontend: Fix trace ID missing from slow query logs, regression from #8618.
 
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