Fix builds due to pip breakage

Author: kadircet

docker/Dockerfile

@@ -4,7 +4,8 @@ RUN apt-get install -y cron python3 python3-requests unzip nginx-light
 # We install pip, jinja and delete pip afterwards in same step to keep final
 # image size small.
 RUN apt-get install -y --no-install-recommends python3-pip && \
-  pip3 install j2cli && apt-get remove -y python3-pip && apt-get autoremove -y
+  pip3 install --break-system-packages j2cli && apt-get remove -y python3-pip \
+  && apt-get autoremove -y
 RUN rm -rf /var/www/html/*
 WORKDIR "/"