Make sure the gh-pages branch is pushed.

    <target name="-push-version">

        <exec executable="git" failonerror="true">

            <arg line="push" />

        </exec>

        <exec executable="git" failonerror="true">

            <arg line="push origin tag ${version-name}" />

            <arg line="push origin HEAD gh-pages tag ${version-name}" />

        </exec>

    </target>