update changes.md

Author: dejii

CHANGES.md

@@ -98,6 +98,7 @@
 
 * Fixed BigQueryEnrichmentHandler batch mode dropping earlier requests when multiple requests share the same enrichment key (Python) ([#38035](https://github.com/apache/beam/issues/38035)).
 * Added `max_batch_duration_secs` passthrough support in Python Enrichment BigQuery and CloudSQL handlers so batching duration can be forwarded to `BatchElements` ([#38243](https://github.com/apache/beam/issues/38243)).
+* Fixed IcebergIO writing manifest column bounds padded with trailing `0x00` bytes, which broke equality predicate pushdown in some query engines (Java) ([#38580](https://github.com/apache/beam/issues/38580)).
 
 ## Security Fixes