anchor.diff:  ADD requirements.txt ./
   RUN pip3 --no-cache-dir install --find-links file://${PWD}/cache -r requirements.txt
   
  -#
  -# Mermaid
  -#
  -RUN yarn add mermaid.cli
  -
   VOLUME /pandoc
   WORKDIR /pandoc
   ADD pandoc.sh /usr/local/bin
  
positive.code:         # required for PDF meta analysis
          poppler-utils \
          zlibc \
          # required for mermaid
          nodejs \
          yarn \
      # clean up
      && apt-get clean && \
      rm -rf /var/lib/apt/lists/* /etc/apt/apt.conf.d/01proxy
  
negative.code: ENV DEBCONF_NOWARNINGS yes
  
  #
  # Debian
  #
  RUN set -x && \
  