Remove the forge repository definition from the release pom

The release pom defines the Hippo Forge repository. This repository definition must be removed.

<repository>
<id>hippo-forge</id>
<name>Hippo Forge maven 2 repository.</name>
<url>https://maven.onehippo.com/maven2-forge/</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
<releases>
<updatePolicy>never</updatePolicy>
</releases>
<layout>default</layout>
</repository>