Docker で　pip がうまく動かない

Quickstart: Compose and DjangoでDockerで起動まではうまくて行ったのですが、挙動がおかしいので何を確認すればいいのか教えていただけますか。

$Task sudo docker-compose run web python -m pip list
Starting task_db_1 ... done
DEPRECATION: The default format will switch to columns in the future. You can use --format=(legacy|columns) (or define a format=(legacy|columns) in your pip.conf under the [list] section) to disable this warning.
Django (2.0.3)
pip (9.0.1)
psycopg2 (2.7.4)
pytz (2018.3)
setuptools (38.5.1)
wheel (0.30.0)
You are using pip version 9.0.1, however version 9.0.2 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.
# pip   が古いようなので更新したのですが
$Task sudo docker-compose run web python3 -m pip install -U pip
Starting task_db_1 ... done
Collecting pip
  Downloading pip-9.0.2-py2.py3-none-any.whl (1.4MB)
    100% |████████████████████████████████| 1.4MB 951kB/s
Installing collected packages: pip
  Found existing installation: pip 9.0.1
    Uninstalling pip-9.0.1:
      Successfully uninstalled pip-9.0.1
Successfully installed pip-9.0.2

# 成功後も結果は変わらず
Task sudo docker-compose run web python3 -m pip list
Starting task_db_1 ... done
DEPRECATION: The default format will switch to columns in the future. You can use --format=(legacy|columns) (or define a format=(legacy|columns) in your pip.conf under the [list] section) to disable this warning.
Django (2.0.3)
pip (9.0.1)
psycopg2 (2.7.4)
pytz (2018.3)
setuptools (38.5.1)
wheel (0.30.0)
You are using pip version 9.0.1, however version 9.0.2 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.

FROM python:3
ENV PYTHONUNBUFFERED 1
RUN mkdir /code
WORKDIR /code
ADD requirements.txt /code/
RUN pip install -r requirements.txt
ADD . /code/