Fail to build skyline image. We should upgrade the pip and setuptools
version.
Remove irrelevant files for skyline-tox-lint-py38 job to retain one job
to trigger zuul.
Refer: https://github.com/python-poetry/poetry/issues/3329
Change-Id: I444faa3aefaa8ef8cfeb5284bc2a7a49bb0cb91b
Since poetry 1.1.8 version introduces a large number of bugs[1], which
makes the process of building container image fail, so the 1.1.8
version of poetry is not used.
[1] https://github.com/python-poetry/poetry/issues/4429
Change-Id: Ia30c2c5e783401aa4bad85139b0bf2fa9a822847