Remove setup.py (#458)

* Remove setup.py

Editable installs for projects with a setup.cfg no longer require a setup.py
shim. This requires pip >= 21.1 (2021-04-24).

* Remove setup.py from blacken and lint sessions

* CI: Use python -m build in deploy job

.github/workflows/ci.yml

@@ -59,10 +59,10 @@ jobs:
         uses: actions/setup-python@v2
         with:
           python-version: 3.9
-      - name: Install setuptools and wheel
-        run: python -m pip install --upgrade --user setuptools wheel
+      - name: Install build
+        run: python -m pip install --user build
       - name: Build sdist and wheel
-        run: python setup.py sdist bdist_wheel
+        run: python -m build
       - name: Publish distribution PyPI
         uses: pypa/gh-action-pypi-publish@master
         with:

noxfile.py

@@ -79,7 +79,7 @@ def cover(session):
 def blacken(session):
     """Run black code formatter."""
     session.install("black==21.5b2", "isort==5.8.0")
-    files = ["nox", "tests", "noxfile.py", "setup.py"]
+    files = ["nox", "tests", "noxfile.py"]
     session.run("black", *files)
     session.run("isort", *files)
 
@@ -96,7 +96,7 @@ def lint(session):
         "importlib_metadata",
     )
     session.run("mypy")
-    files = ["nox", "tests", "noxfile.py", "setup.py"]
+    files = ["nox", "tests", "noxfile.py"]
     session.run("black", "--check", *files)
     session.run("isort", "--check", *files)
     session.run("flake8", *files)