docs: update CHANGELOG.md

Author: karel-rehor

CHANGELOG.md

@@ -1,5 +1,12 @@
 ## 1.6.0 [unreleased]
 
+### Features
+
+1. [#306](https://github.com/InfluxCommunity/influxdb3-java/pull/306): Improve closing of Arrow `FlightStream`.
+   1. Track new streams in an AutoCloseable list.
+   2. Close streams automatically when they are empty.
+   3. Ensure that references to closed streams are regularly removed to aid garbage collection.
+
 ## 1.5.0 [2025-10-22]
 
 ### Features