update changelog

Author: sebhahn

CHANGELOG.rst

@@ -2,13 +2,20 @@
 Changelog
 =========
 
+Version 2.6.5
+=============
+
+- Add test class reading ASCAT data in zarr format
+
 Version 2.6.4
 =============
+
 - Update `product_info.AscatH129Swath.sf_pattern` and `.sf_read_fmt` to match operational
   product; update tests to match
 
 Version 2.6.3
 =============
+
 - Update `product_info.AscatH129Swath.fn_pattern` to match operational product; update
   tests to match