Add changelog

Author: deguif

CHANGELOG-6.0.md

@@ -9,6 +9,7 @@ in 6.0 versions.
 * Added support for queued messages via Symfony Messenger.
 * Fixed several Doctrine Persistence deprecations.
 * Fixed missing options in `findHybridPaginated`.
+* **[BC break]** Marked the `fos_elastica.config_manager` service as private.
 * **[BC break]** Marked the `fos_elastica.filter_objects_listener` service as private.
 * **[BC break]** The configuration option `debug_logging` must be a boolean instead of a scalar value.