fix(Poetry): Poetry cache in GitLab CI cache

  # Change pip's cache directory to be inside the project directory since we can

  # only cache local items.

  PIP_CACHE_DIR: "$CI_PROJECT_DIR/.cache/pip"

  # Poetry support: force virtualenv not in project dir & use local cache dir

  POETRY_CACHE_DIR: "$CI_PROJECT_DIR/.cache/poetry"

  POETRY_VIRTUALENVS_IN_PROJECT: "false"

  PYTHON_IMAGE: python:3

  # Default Python project root directory

  PYTHON_PROJECT_DIR: .

    key: "$CI_COMMIT_REF_SLUG-python"

    paths:

      - ${PIP_CACHE_DIR}

      - ${POETRY_CACHE_DIR}

  before_script:

    - *python-scripts

    - install_ca_certs "${CUSTOM_CA_CERTS:-$DEFAULT_CA_CERTS}"