prepare v6.2.3 release notes (#1007)

Author: FZambia

misc/release/notes.md

@@ -10,14 +10,17 @@ For details, go to the [Centrifugo documentation site](https://centrifugal.dev).
 
 ### Improvements
 
-* Option to use try lock for postgresql consumer, [#988](https://github.com/centrifugal/centrifugo/pull/988). New option for PG consumer `use_try_lock` (boolean, default `false`) to use `pg_try_advisory_xact_lock` instead of `pg_advisory_xact_lock` for locking outbox table. This may help to reduce the number of long-running transactions on PG side.
+* Use our internal fork of the Gorilla WebSocket library for unidirectional WebSocket transport, which provides slightly better Upgrade performance [#1005](https://github.com/centrifugal/centrifugo/pull/1005). The fork was previously used only for bidirectional WebSocket transport.
+* Kafka consumer: introduce a per-partition size-limited queue for backpressure and a configurable `fetch_max_wait` [#997](https://github.com/centrifugal/centrifugo/pull/997). Centrifugo now polls Kafka with `500ms` by default and avoids using the `SetOffsets` API of the `franz-go` library. Instead of a buffered channel, we now use a queue (limited by size, configured over `partition_queue_max_size`). The `partition_buffer_size` option was removed since the internal consumer implementation changed, but we do not expect this to be a problem for users based on the added benchmark and improved throughput in the new implementation. However, it may result in a warning in logs about using the non-existing `partition_buffer_size` option, which may be an inconvenience. See [updated docs](https://centrifugal.dev/docs/server/consumers#kafka-consumer).
+* Kafka consumer: switch to ReadCommitted mode for consuming by default, adding a boolean `fetch_read_uncommitted` option to consume with ReadUncommitted mode [#1001](https://github.com/centrifugal/centrifugo/pull/1001). See [updated docs](https://centrifugal.dev/docs/server/consumers#kafka-consumer).
 
 ### Fixes
 
-* Fix log entries about engine on start [#992](https://github.com/centrifugal/centrifugo/pull/992).
+* Fix Kubernetes environment variable regex by @yinheli [#1003](https://github.com/centrifugal/centrifugo/pull/1003) – in some cases, this allows avoiding extra warnings in logs about variables with the `CENTRIFUGO_` prefix automatically injected by the K8S runtime.
+* Fix panic when using the server `subscribe` API during Redis unavailability [#centrifugal/centrifuge#491](https://github.com/centrifugal/centrifuge/pull/491)
 
 ### Miscellaneous
 
-* This release is built with Go 1.24.4.
+* This release is built with Go 1.24.5.
 * Updated dependencies.
-* See also the corresponding [Centrifugo PRO release](https://github.com/centrifugal/centrifugo-pro/releases/tag/v6.2.2).
+* See also the corresponding [Centrifugo PRO release](https://github.com/centrifugal/centrifugo-pro/releases/tag/v6.2.3).