build: Add 'model' to groupId

pom.xml

@@ -8,7 +8,7 @@
         <version>1.0.0</version>
     </parent>
 
-    <groupId>no.nibio.vips</groupId>
+    <groupId>no.nibio.vips.model</groupId>
     <artifactId>GrassDryingModel</artifactId>
     <version>2.0.0</version>
     <packaging>jar</packaging>