Ignore negative level structures in DeReKo#structure.xml

Change-Id: I93a4c13c919c49092edee00a7f0c3d50dbc9a1fe
diff --git a/Changes b/Changes
index 2adee64..7971f0b 100644
--- a/Changes
+++ b/Changes
@@ -1,5 +1,7 @@
-0.42 2020-11-03
+0.42 2021-02-16
         - Replaced Log4perl with Log::Any.
+        - Ignore level < 0 structures in DeReKo, but support
+          them for base annotations.
 
 0.41 2020-08-10
         - Added support for RWK annotations.