$config = new DOMDocument;
        $config->load(
          JENKINS_URL . '/job/' . JENKINS_JOB_NAME . '-master/config.xml'
        );

        $xpath = new DOMXPath($config);
        $node  = $xpath->query(
          'scm/branches/hudson.plugins.git.BranchSpec/name'
        );

        $node->item(0)->replaceChild(
          new DOMText($branch), $node->item(0)->firstChild
        );

        $config = $config->saveXML();