[regression] command line option "-update-snapshots" does not work for dependency:copy-dependencies

<plugin>
  <artifactId>maven-dependency-plugin</artifactId>
  <version>2.0</version>
  <executions>
    <execution>
      <id>copy</id>
      <phase>initialize</phase>
      <goals>
        <goal>copy</goal>
      </goals>
      <configuration>
        <artifactItems>
          <artifactItem>
            <groupId>org.apache.maven</groupId>
            <artifactId>maven-model</artifactId>
            <version>3.0-SNAPSHOT</version>
            <type>jar</type>
            <overWrite>true</overWrite>
          </artifactItem>
        </artifactItems>
        <overWriteSnapshots>true</overWriteSnapshots>
      </configuration>
    </execution>
  </executions>
</plugin>