Update Dockerfile so that it uses latest Python.

Simplify the remaining of the file and make it buildable on Windows10

Dockerfile

@@ -1,30 +1,22 @@
 # Get the base Python image
-FROM python:3.7
+FROM python:latest
 
 # Set the working directory in the container
-RUN useradd -ms /bin/bash msspec
 WORKDIR /code
 
 # Fetch the code
-COPY fresh .
-
-ENV LANG=en_US.UTF-8
-ENV PATH=/opt/bin:$PATH
+RUN git clone --branch devel https://git.ipr.univ-rennes1.fr/epsi/msspec_python3.git .
 
 # Install system dependencies
-RUN apt-get update && \
-    apt-get install -y virtualenv gfortran locales python3-wxgtk4.0
-
-# Reconfigure the locales
-RUN sed -i -e "s/# $LANG.*/$LANG UTF-8/" /etc/locale.gen && \
-    dpkg-reconfigure --frontend=noninteractive locales && \
-    update-locale LANG=$LANG
+RUN apt-get update && apt-get install -y virtualenv gfortran libgtk-3-dev
     
 # Install msspec
+ENV PATH=/opt/bin:$PATH
 RUN make install VERBOSE=1 INSTALL_PREFIX=/opt
 
-#RUN echo "/usr/lib/python3/dist-packages" > /opt/src/msspec_venv_*/lib/python3.7/site-packages/system_packages.pth
-
+# Add a non-privileged user
+RUN useradd -ms /bin/bash msspec
 USER msspec
 
+# Run the msspec frontend command on startup
 ENTRYPOINT ["msspec"]