如何将很长的甘特图分成连续的行？

Question

我需要一个长期（例如一年多）项目的甘特图。

考虑以下MWE：

\documentclass[12pt]{article}
\usepackage[margin=1.0in]{geometry}
\usepackage{pgfgantt}
\usepackage{pdflscape}
\usepackage{capt-of} %caption outside floats
\begin{document}
    \begin{landscape}
        \captionof{figure}{My Timeline}
        \begin{tikzpicture}
        \begin{ganttchart}[%%%
        hgrid,
        vgrid,
        x unit=4mm,
        time slot format=isodate,
        title/.append style={shape=rectangle, fill=black!10},
        title height=1,
        bar/.append style={fill=green!70},
        bar height=.6,
        bar label font=\normalsize\color{black!90},
        group top shift=.6,
        group height=.3,
        group peaks height=.2,
        ]{2017-04-01}{2018-08-01}
        14
        \gantttitlecalendar{year, month, day} \\
        \ganttbar{Task}{2018-05-15}{2018-05-25}                    
        \end{ganttchart}
        \end{tikzpicture}
    \end{landscape}
\end{document}

有没有办法将甘特图分成多条连续的线以覆盖所有目标期？