modern version of the maven-war-plugin apparently doesn't add the version, so...

modern version of the maven-war-plugin apparently doesn't add the version, so adding it back on my own

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@22518 71c3de6d-444a-0410-be80-ed276b4c234a

war/pom.xml

@@ -64,6 +64,9 @@ THE SOFTWARE.
             <manifest>
               <mainClass>Main</mainClass>
             </manifest>
+            <manifestEntries>
+              <Implementation-Version>${project.version}</Implementation-Version>
+            </manifestEntries>
           </archive>
           <!--outputFileNameMapping>@{artifactId}@.@{extension}@</outputFileNameMapping-->
         </configuration>