fix missing files in maven build

Author: stoecker

pom.xml

@@ -11,6 +11,7 @@
   <properties>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     <plugin.src.dir>src/main/java</plugin.src.dir>
+    <plugin.resources.dir>src/main/resources</plugin.resources.dir>
     <plugin.main.version>19044</plugin.main.version>
     <plugin.author>Biswesh Mohapatra &lt;biswesh123@gmail.com&gt;, simon04, Rodion Scherbakov</plugin.author>
     <plugin.class>org.openstreetmap.josm.plugins.pt_assistant.PTAssistantPlugin</plugin.class>