Base images, stages. and cache

.gitlab-ci.yml

image: python:latest

stages:
    - test
    - flake8
    - build
    - sonarqube
    - deploy

variables:
  PIP_CACHE_DIR: "$CI_PROJECT_DIR/.cache/pip"
  DOCKER_DRIVER: overlay2

cache:
  paths:
    - .cache/pip
    - venv/

before_script:
  - python -V                       
  - pip install virtualenv
  - virtualenv venv
  - source venv/bin/activate
  - pip install -r requirements.txt...