1) In kie-parent-metadata's pom.xml, remove the repository jboss-deprecated:

     <repository>
      <id>jboss-deprecated</id>
      <name>JBoss Deprecated</name>
      <url>https://repository.jboss.org/nexus/content/repositories/deprecated/</url>
      <releases>
        <enabled>true</enabled>
        <updatePolicy>never</updatePolicy>
      </releases>
      <snapshots>
        <enabled>false</enabled>
      </snapshots>
    </repository>

https://github.com/droolsjbpm/droolsjbpm-build-bootstrap/blob/master/pom.xml#L88

2) remove your local repository
3) Do a mvn-all.sh -Dfull clean install

If it works, commit the change.
If it doesn't, make a list of dependencies that are still coming from the jboss-deprecated repository and make for each dependency a JIRA (or Bugzilla) issue calling to remove it. Tell the module owners who use those deprecated dependencies about the JIRA/BZ and ask them to remove the deprecated dependency.