git-svn-id: https://svn.apache.org/repos/asf/maven/maven-1/plugins/trunk@345717 13f79535-47bb-0310-9956-ffa450edef68
Every pom that does not extend another one (a 'root' pom) has to comply
with the schema ${plugin.resources}/xsd/pom-strict-${pom.pomVersion}.xsd.
A child pom (a pom that extends another one) has to comply
with the schema ${maven.home}/maven-project-${pom.pomVersion}.xsd.