Dockerfile: Ubuntu 18.04 with Python 3.10 as Default

FROM ubuntu:18.04

RUN apt-get update && apt-get -y upgrade && \ apt-get -y install python3.10 && \ update-alternatives --install /usr/bin/python3 python3 /usr/bin/python3.10 1 && \ apt-get -y autoremove && \ apt-get -y clean && \ rm -rf /var/lib/apt/lists/*

CMD [ 'python3' ]