Make sure you have the Forge Maven 2 repository reference and dependency definition in the root pom.xml of your project.
<repositories>
<!-- SNIP -->
<repository>
<id>hippo-maven2</id>
<name>Hippo Maven 2 Repository</name>
<url>https://maven.bloomreach.com/maven2/</url>
</repository>
<!-- SNIP -->
</repositories>
<!-- SNIP -->
<dependencyManagement>
<!-- SNIP -->
<dependencies>
<!-- SNIP -->
<!-- NOTE: You should set a property named 'forge.channel-pagesup.version' to a version of this plugin! -->
<!-- DocumentManagementService as CMS application side dependency -->
<dependency>
<groupId>org.onehippo.forge.channel-pagesup</groupId>
<artifactId>channel-pagesup-document-management-service</artifactId>
<version>${forge.channel-pagesup.version}</version>
</dependency>
<!-- CopyPageEvent handler as SITE application side dependency -->
<dependency>
<groupId>org.onehippo.forge.channel-pagesup</groupId>
<artifactId>channel-pagesup-channel-page-event</artifactId>
<version>${forge.channel-pagesup.version}</version>
</dependency>
<!-- SNIP -->
</dependencies>
<!-- SNIP -->
</dependencyManagement>
And add the following dependency reference into your CMS dependencies module pom.
<dependencies>
<!-- SNIP -->
<!-- DocumentManagementService as CMS application side dependency -->
<dependency>
<groupId>org.onehippo.forge.channel-pagesup</groupId>
<artifactId>channel-pagesup-document-management-service</artifactId>
</dependency>
<!-- SNIP -->
</dependencies>
And add the following dependency reference into your SITE components module pom.
<dependencies>
<!-- SNIP -->
<!-- CopyPageEvent handler as SITE application side dependency -->
<dependency>
<groupId>org.onehippo.forge.channel-pagesup</groupId>
<artifactId>channel-pagesup-channel-page-event</artifactId>
</dependency>
<!-- SNIP -->
</dependencies>
Now, you're ready to use the plugin!