Update CHANGELOG

Author: ChrisFairless

CHANGELOG.md

@@ -35,6 +35,7 @@ Code freeze date: YYYY-MM-DD
   - latitude and longitude column are no longer present there (the according arrays can be retrieved as properties of the Exposures object: `exp.latitude` instead of `exp.gdf.latitude.values`).
   - `Exposures.gdf` has been renamed to `Exposures.data` (it still works though, as it is a property now pointing to the latter)
   - the `check` method does not add a default "IMPF_" column to the GeoDataFrame anymore
+- Updated IBTrACS version from v4.0 to v4.1
 
 ### Fixed