Add changelog entry

CHANGELOG.md

@@ -209,6 +209,7 @@
   * `operation_duration_seconds`
 * [ENHANCEMENT] Add `outcome` label to `gate_duration_seconds` metric. Possible values are `rejected_canceled`, `rejected_deadline_exceeded`, `rejected_other`, and `permitted`. #512
 * [ENHANCEMENT] Expose `InstancesWithTokensCount` and `InstancesWithTokensInZoneCount` in `ring.ReadRing` interface. #516
+* [ENHANCEMENT] Middleware: determine route name in a single place, and add `middleware.ExtractRouteName()` method to allow consuming applications to retrieve the route name. #527
 * [BUGFIX] spanlogger: Support multiple tenant IDs. #59
 * [BUGFIX] Memberlist: fixed corrupted packets when sending compound messages with more than 255 messages or messages bigger than 64KB. #85
 * [BUGFIX] Ring: `ring_member_ownership_percent` and `ring_tokens_owned` metrics are not updated on scale down. #109