python3-pip now requires python3-distutils

[Thomas Riccardi]

```
$ docker pull ubuntu:18.04
18.04: Pulling from library/ubuntu
Digest: sha256:c8c275751219dadad8fa56b3ac41ca6cb22219ff117ca98fe82b42f24e1ba64e
Status: Downloaded newer image for ubuntu:18.04
$ docker run -it --rm ubuntu:18.04 bash
# apt-get update && apt-get install -y --no-install-recommends python3 python3-pip
# pip3 -h
Traceback (most recent call last):
  File "/usr/bin/pip3", line 9, in <module>
    from pip import main
  File "/usr/lib/python3/dist-packages/pip/__init__.py", line 26, in <module>
    from pip.utils import get_installed_distributions, get_prog
  File "/usr/lib/python3/dist-packages/pip/utils/__init__.py", line 23, in <module>
    from pip.locations import (
  File "/usr/lib/python3/dist-packages/pip/locations.py", line 9, in <module>
    from distutils import sysconfig
ImportError: cannot import name 'sysconfig'
```

It seems that python3-pip now requires `python3-distutils` (instead of being just a recommendation via `python3-setuptools` own recommendation):
```
$ docker run -it --rm ubuntu:18.04 bash
# apt-get update && apt-get install -y --no-install-recommends python3 python3-pip python3-distutils
# pip3 -h

Usage:
  pip <command> [options]

...

```

The same scenario worked with ubuntu:16.04.

[Thomas Riccardi (thomas-riccardi-deepomatic)]

It is fixed since `python3-pip - 9.0.1-2.3~ubuntu1`, tracked on https://bugs.launchpad.net/ubuntu/+source/python-pip/+bug/1771624

[Scott Kitterman (kitterman)]

Fixed in focal and later.