DOC: update changelog with fixed xls error #52

CHANGELOG.md

@@ -67,6 +67,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * #40 Insertion of identifiables with missing obligatory properties
 - Before, a Property with the datatype "LIST(TEXT)" would lead to the creation 
   of a RecordType. This is fixed now.
+* #52 `XLSimporter.read_xls` throwed a wrong error when reading from a file with a wrong ending. 
+  Now, a `DataInconsistencyError` is raised instead of a ValueError.
 
 ### Security ###