Remove PEP517 isolation from sgmllib3k

.github/workflows/pipeline.yml

@@ -30,7 +30,7 @@ jobs: # jobs. We will have two jobs (test and publish) with multiple steps.
           poetry config virtualenvs.create false --local
           poetry run python -m pip install --upgrade pip wheel setuptools
           # Because Poetry won't fix this https://github.com/python-poetry/poetry/issues/3433
-          poetry run python -m pip install --no-use-pep517 "sgmllib3k (==1.0.0)"
+          python -m pip install "sgmllib3k (==1.0.0)"
           poetry install --all-extras
           pip install pytest pylint coverage mypy coveralls
       #   python -m nltk.downloader punkt stopwords