diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 41e8200..7c33570 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -76,12 +76,12 @@ jobs:
     - name: Install wheel
       run: |
         python -m pip install --upgrade pip
-        pip install wheel
+        pip install build
     - name: Build package
       run: |
-        python setup.py sdist bdist_wheel
+        python -m build
     - name: Publish package to PyPI
-      uses: pypa/gh-action-pypi-publish@master
+      uses: pypa/gh-action-pypi-publish@release/v1
       with:
         user: __token__
         password: ${{ secrets.pypi_token }}
diff --git a/pyproject.toml b/pyproject.toml
index b3e6209..19ee000 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,5 @@
 [build-system]
 requires = [
-  # sync with setup.py until we discard non-pep-517/518
   "setuptools>=45.0",
   "setuptools-scm[toml]>=6.2.3",
   "wheel",
diff --git a/setup.cfg b/setup.cfg
index 88871d1..094de03 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -44,7 +44,6 @@ python_requires = >=3.6
 install_requires =
     execnet>=1.1
     pytest>=6.2.0
-setup_requires = # left empty, enforce using isolated build system
 
 [options.packages.find]
 where = src
diff --git a/setup.py b/setup.py
deleted file mode 100644
index 7f1a176..0000000
--- a/setup.py
+++ /dev/null
@@ -1,4 +0,0 @@
-from setuptools import setup
-
-if __name__ == "__main__":
-    setup()
diff --git a/src/xdist/plugin.py b/src/xdist/plugin.py
index a4e9284..a24864e 100644
--- a/src/xdist/plugin.py
+++ b/src/xdist/plugin.py
@@ -18,7 +18,9 @@ def pytest_xdist_auto_num_workers(config):
         try:
             return int(env_var)
         except ValueError:
-            warnings.warn("PYTEST_XDIST_AUTO_NUM_WORKERS is not a number: {env_var!r}. Ignoring it.")
+            warnings.warn(
+                "PYTEST_XDIST_AUTO_NUM_WORKERS is not a number: {env_var!r}. Ignoring it."
+            )
 
     try:
         import psutil
diff --git a/src/xdist/remote.py b/src/xdist/remote.py
index edf6ae3..5d0c899 100644
--- a/src/xdist/remote.py
+++ b/src/xdist/remote.py
@@ -28,8 +28,8 @@ class Producer:
     """
     Simplified implementation of the same interface as py.log, for backward compatibility
     since we dropped the dependency on pylib.
-    Note: this is defined here because this module can't depend on xdist, so we need 
-    to have the other way around.    
+    Note: this is defined here because this module can't depend on xdist, so we need
+    to have the other way around.
     """
 
     def __init__(self, name: str, *, enabled: bool = True):
diff --git a/testing/test_plugin.py b/testing/test_plugin.py
index 0ed8329..c17a273 100644
--- a/testing/test_plugin.py
+++ b/testing/test_plugin.py
@@ -12,7 +12,8 @@ import pytest
 @pytest.fixture
 def monkeypatch_3_cpus(monkeypatch: pytest.MonkeyPatch):
     """Make pytest-xdist believe the system has 3 CPUs"""
-    monkeypatch.setitem(sys.modules, "psutil", None)  # block import
+    # block import
+    monkeypatch.setitem(sys.modules, "psutil", None)  # type: ignore
     monkeypatch.delattr(os, "sched_getaffinity", raising=False)
     monkeypatch.setattr(os, "cpu_count", lambda: 3)