Call out OutputBuilder change in CHANGES.md

Author: Abacn

CHANGES.md

@@ -87,6 +87,7 @@
 * Removed deprecated Hadoop versions (2.10.2 and 3.2.4) that are no longer supported for [Iceberg](https://github.com/apache/iceberg/issues/10940) from IcebergIO ([#36282](https://github.com/apache/beam/issues/36282)).
 * (Go) Coder construction on SDK side is more faithful to the specs from runners without stripping length-prefix. This may break streaming pipeline update as the underlying coder could be changed ([#36387](https://github.com/apache/beam/issues/36387)).
 * Minimum Go version for Beam Go updated to 1.25.2 ([#36461](https://github.com/apache/beam/issues/36461)).
+* (Java) DoFn OutputReceiver interfaces now requires implementing a builder method as part of extended metadata support for elements ([#34902](https://github.com/apache/beam/issues/34902)).
 
 ## Deprecations