update dockerfile to render jupyter notebook equations (alshedivat#2758)

Hello,

This pr should address the issue where the equations in jupter notebooks
were not being rendered correctly in issue
alshedivat#2757 .

Dockerfile

@@ -8,9 +8,10 @@ RUN apt-get update -y && apt-get install -y --no-install-recommends \
     imagemagick \
     build-essential \
     zlib1g-dev \
-    jupyter-nbconvert \
+    python3-pip \
     inotify-tools procps && \
-    apt-get clean && rm -rf /var/lib/apt/lists/* /var/cache/apt/archives/*
+    apt-get clean && rm -rf /var/lib/apt/lists/* /var/cache/apt/archives/* && \
+    pip install nbconvert --break-system-packages
 
 
 RUN sed -i '/en_US.UTF-8/s/^# //g' /etc/locale.gen && \