Before this change:

    $ dabuild sh
    $ sudo apk add speedtest-cli >/dev/null && speedtest-cli --version
    env: can't execute 'python': No such file or directory
    $ speedtest --version
    Traceback (most recent call last):
      File "/usr/bin/speedtest", line 6, in <module>
        from pkg_resources import load_entry_point
    ModuleNotFoundError: No module named 'pkg_resources'

This change removes the specific install line for speedtest-cli, because
it leaves a broken shebang first line. setup.py already installs a
speedtest-cli script which a functional shebang line.

This change adds py3-setuptools as a runtime dependency because
pkg_resources is imported by a file installed into /usr/bin/:

    $ grep pkg_resources /usr/bin/speedtest
    from pkg_resources import load_entry_point

pkg_resources is part of py3-setuptools:

    $ apk info -L py3-setuptools | grep pkg_resources/__init__.py
    usr/lib/python3.8/site-packages/pkg_resources/__init__.py

After this change:

    $ dabuild sh
    $ sudo apk add speedtest-cli >/dev/null && speedtest-cli --version
    speedtest-cli 2.1.2
    Python 3.8.2 (default, Apr  9 2020, 21:05:08) [GCC 9.3.0]
    $ speedtest --version
    speedtest-cli 2.1.2
    Python 3.8.2 (default, Apr  9 2020, 21:05:08) [GCC 9.3.0]

and modify APKBUILD