mcMMO/src/main/assembly/package.xml

<assembly 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>bin</id>
    <includeBaseDirectory>false</includeBaseDirectory>
    <formats>
        <format>zip</format>
    </formats>
    <files>
        <file>
            <source>${project.build.directory}/${artifactId}.jar</source>
            <outputDirectory>/</outputDirectory>
            <destName>mcMMO.jar</destName>
        </file>
    </files>
</assembly>