Add docs

Signed-off-by: Auni Ahsan <[email protected]>

docs/root/version_history/current.rst

@@ -93,6 +93,7 @@ New Features
 * http: added support for `Envoy::ScopeTrackedObject` for HTTP/1 and HTTP/2 dispatching. Crashes while inside the dispatching loop should dump debug information.
 * http: added support for :ref:`preconnecting <envoy_v3_api_msg_config.cluster.v3.Cluster.PreconnectPolicy>`. Preconnecting is off by default, but recommended for clusters serving latency-sensitive traffic, especially if using HTTP/1.1.
 * http: change frame flood and abuse checks to the upstream HTTP/2 codec to ON by default. It can be disabled by setting the `envoy.reloadable_features.upstream_http2_flood_checks` runtime key to false.
+* http filter: add function to `NamedHttpFilterConfigFactory` which can be overridden to return a :ref`FilterDependencies <envoy_api_file_envoy/extensions/filters/common/dependency/v3/dependency.proto>` specification. Config-plane validation of dependencies is currently WIP.
 * json: introduced new JSON parser (https://github.com/nlohmann/json) to replace RapidJSON. The new parser is disabled by default. To test the new RapidJSON parser, enable the runtime feature `envoy.reloadable_features.remove_legacy_json`.
 * original_dst: added support for :ref:`Original Destination <config_listener_filters_original_dst>` on Windows. This enables the use of Envoy as a sidecar proxy on Windows.
 * overload: add support for scaling :ref:`transport connection timeouts<envoy_v3_api_enum_value_config.overload.v3.ScaleTimersOverloadActionConfig.TimerType.TRANSPORT_SOCKET_CONNECT>`. This can be used to reduce the TLS handshake timeout in response to overload.