Remove 'du' from abbreviation list

Change-Id: I6873861bd6bc51260acca9a9046a3dc72b8b79ac
diff --git a/pom.xml b/pom.xml
index e5563a2..652b63c 100644
--- a/pom.xml
+++ b/pom.xml
@@ -6,7 +6,7 @@
 
     <groupId>groupId</groupId>
     <artifactId>KorAP-Tokenizer</artifactId>
-    <version>2.2.0.9000</version>
+    <version>2.2.1</version>
 
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>