Change pom groupId to de.ids-mannheim.korap.tokenizer

The groupId in the pom is unrelated to java package and may contain
hyphens.

This facilitates the upload to Maven Central.

Change-Id: Id97f600a612b26e11fac8d12960fd6f62fc7535a
diff --git a/pom.xml b/pom.xml
index 5fafa48..1a7c152 100644
--- a/pom.xml
+++ b/pom.xml
@@ -2,7 +2,7 @@
 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
 
-    <groupId>de.ids_mannheim.korap.tokenizer</groupId>
+    <groupId>de.ids-mannheim.korap.tokenizer</groupId>
     <artifactId>KorAP-Tokenizer</artifactId>
     <version>2.2.4-SNAPSHOT</version>