Add id to assembly fixes #10

Changing versions of the maven-assembly-plugin broke the build when
using newer versions. Versions after 2.4.1 (which is actually an ancient
version) require an assembly description to have an id. Set id to
'update-site-assembly' and set 'appendAssemblyId' to false. This uses a
correct id for the build, but stops maven from appending the id to the
finished zip. Just makes the file name unncesserily long and adds no
value.

I don't really know why this hasn't broken the build before, because we
never actually used a version older than 2.4.1. Will very likely be a
problem in builds that inherited from this project.

src/main/resources/archetype-resources/update-site/pom.xml

@@ -27,6 +27,7 @@
 			<plugin>
 				<artifactId>maven-assembly-plugin</artifactId>
 				<configuration>
+                    <appendAssemblyId>false</appendAssemblyId>
 					<descriptors>
 						<descriptor>templates/zip.xml</descriptor>
 					</descriptors>

src/main/resources/archetype-resources/update-site/templates/zip.xml

@@ -2,6 +2,7 @@
 	xmlns="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.0"
 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 	xsi:schemaLocation="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.0 http://maven.apache.org/xsd/assembly-1.1.0.xsd">
+    <id>update-site-assembly</id>
 	<baseDirectory>/</baseDirectory>
 	<formats>
 		<format>zip</format>