use the Debian version of flask/flask-cors

docker/Dockerfile

@@ -6,6 +6,7 @@ RUN echo 'deb [trusted=true] http://www.lrde.epita.fr/repo/debian/ stable/' >> /
       apt-get install -y --allow-unauthenticated --no-install-recommends \
       fonts-lato spot python3-spot spot-doc lighttpd graphviz libbdd0c2 \
       uwsgi uwsgi-plugin-python3 python3-pip python3-setuptools vim unzip \
+      python3-flask python3-flask-cors \
     && apt-get clean
 
 COPY install.sh /tmp/install.sh

docker/install.sh

@@ -12,8 +12,6 @@ cp -R /usr/share/doc/python3-spot/examples/*.html ipynb
 
 gzip -cd /usr/share/doc/spot/tl/tl.pdf.gz > tl.pdf
 
-pip3 install flask flask-cors
-
 cat >/etc/lighttpd/lighttpd.conf <<\EOF
 server.modules = (
         "mod_access",