fix: Dockerfile with ENTRYPOINT only section

[jrcoding]

This is for convenience and alternatively to PR #51

AFAIK the combination of ENTRYPOINT and CMD section in Dockerfile only makes sense if one needs the feature to overwrite the default command, specified by CMD, with a different one i.e. something like analyze_test.py specified on the command line. My impression is, that this is never the case here, right? If I'm right, it may be better to to go back in Dockerfile to ENTRYPOINT [ "python3" , "./analyze.py" ] and leave README.md as it is?!