The plugin isn’t bundled with any script engine, instead it should be added as dependency to the plugin.
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-scripting-plugin</artifactId>
<version>@project.version@</version>
<executions>
<execution>
<id>groovy</id>
<configuration>
<engineName>groovy</engineName>
<script>
<![CDATA[
(1..10).sum() + ' ' + project.artifactId
]]>
</script>
</configuration>
</execution>
</executions>
<dependencies>
<!-- ScriptEngines -->
<dependency>
<groupId>org.codehaus.groovy</groupId>
<artifactId>groovy-jsr223</artifactId>
<version>3.0.7</version> <!-- look for latest -->
</dependency>
</dependencies>
</plugin>