Moved checkstyle config to src/main/config

dddsample/pom.xml

@@ -328,7 +328,7 @@
       <plugin>
         <artifactId>maven-checkstyle-plugin</artifactId>
         <configuration>
-          <configLocation>checkstyle.xml</configLocation>
+          <configLocation>src/main/config/checkstyle.xml</configLocation>
           <!-- Java source code generated from WSDL -->
           <excludes>**/com/aggregator/**/*</excludes>
         </configuration>