docs: Add missing changelog entry for mTLS memcached addition (#12377)

CHANGELOG.md

@@ -61,6 +61,7 @@
 * [11817](https://github.com/grafana/loki/pull/11817) **ashwanthgoli** Ruler: Add support for filtering results of `/prometheus/api/v1/rules` endpoint by rule_name, rule_group, file and type.
 * [11897](https://github.com/grafana/loki/pull/11897) **ashwanthgoli** Metadata: Introduces a separate split interval of `split_recent_metadata_queries_by_interval` for `recent_metadata_query_window` to help with caching recent metadata query results.
 * [11970](https://github.com/grafana/loki/pull/11897) **masslessparticle** Ksonnet: Introduces memory limits to the compactor configuration to avoid unbounded memory usage.
+* [12318](https://github.com/grafana/loki/pull/12318) **DylanGuedes** Memcached: Add mTLS support.
 
 ##### Fixes
 * [11074](https://github.com/grafana/loki/pull/11074) **hainenber** Fix panic in lambda-promtail due to mishandling of empty DROP_LABELS env var.