diff --git a/.editorconfig b/.editorconfig
new file mode 100644
index 0000000000..6385b57343
--- /dev/null
+++ b/.editorconfig
@@ -0,0 +1,15 @@
+root = true
+
+[*]
+charset = utf-8
+indent_style = tab
+indent_size = 4
+insert_final_newline = true
+end_of_line = lf
+
+[*.py]
+indent_style = space
+
+[*.{yml,yaml}]
+indent_style = space
+indent_size = 2
diff --git a/pytest.ini b/pytest.ini
index 03fc773cf4..9aa1b17347 100644
--- a/pytest.ini
+++ b/pytest.ini
@@ -8,8 +8,6 @@ doctest_optionflags=ALLOW_UNICODE ELLIPSIS
 # workaround for warning pytest-dev/pytest#6178
 junit_family=xunit2
 filterwarnings=
-    # https://github.com/pytest-dev/pytest/issues/6928
-    ignore:direct construction of .*Item has been deprecated:DeprecationWarning
     # Fail on warnings
     error
     # https://github.com/pypa/setuptools/issues/1823
diff --git a/setup.cfg b/setup.cfg
index 7b05eed32f..cfb9e078a9 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -1,6 +1,6 @@
 [metadata]
 license_files =
-    LICENSE
+	LICENSE
 name = setuptools
 version = 54.1.1
 author = Python Packaging Authority
@@ -14,13 +14,13 @@ classifiers =
 	License :: OSI Approved :: MIT License
 	Programming Language :: Python :: 3
 	Programming Language :: Python :: 3 :: Only
-    Topic :: Software Development :: Libraries :: Python Modules
-    Topic :: System :: Archiving :: Packaging
-    Topic :: System :: Systems Administration
-    Topic :: Utilities
+	Topic :: Software Development :: Libraries :: Python Modules
+	Topic :: System :: Archiving :: Packaging
+	Topic :: System :: Systems Administration
+	Topic :: Utilities
 keywords = CPAN PyPI distutils eggs package management
 project_urls =
-    Documentation = https://setuptools.readthedocs.io/
+	Documentation = https://setuptools.readthedocs.io/
 
 [options]
 packages = find_namespace:
@@ -31,52 +31,56 @@ install_requires =
 
 [options.packages.find]
 exclude =
-        build*
-        docs*
-        tests*
-        *.tests
-        tools*
+	build*
+	dist*
+	docs*
+	tests*
+	*.tests
+	tools*
 
 [options.extras_require]
 testing =
 	# upstream
-	pytest >= 3.5, !=3.7.3
+	pytest >= 4.6
 	pytest-checkdocs >= 2.4
 	pytest-flake8
+	# python_implementation: workaround for jaraco/skeleton#22
 	pytest-black >= 0.3.7; python_implementation != "PyPy"
 	pytest-cov
-	pytest-mypy; python_implementation != "PyPy"
+	# python_implementation: workaround for jaraco/skeleton#22
+	# python_version: workaround for python/typed_ast#156
+	pytest-mypy; python_implementation != "PyPy" and python_version < "3.10"
 	pytest-enabler >= 1.0.1
 
 	# local
-    mock
-    flake8-2020
-    virtualenv>=13.0.0
-    pytest-virtualenv>=1.2.7
-    wheel
-    paver
-    pip>=19.1 # For proper file:// URLs support.
-    jaraco.envs
-    pytest-xdist
-    sphinx
-    jaraco.path>=3.2.0
+	mock
+	flake8-2020
+	virtualenv>=13.0.0
+	pytest-virtualenv>=1.2.7
+	wheel
+	paver
+	pip>=19.1 # For proper file:// URLs support.
+	jaraco.envs
+	pytest-xdist
+	sphinx
+	jaraco.path>=3.2.0
 
 docs =
-    # Keep these in sync with docs/requirements.txt
+	# Keep these in sync with docs/requirements.txt
 	# upstream
 	sphinx
 	jaraco.packaging >= 8.2
 	rst.linker >= 1.9
-    sphinx-inline-tabs
+	sphinx-inline-tabs
 
 	# local
-    pygments-github-lexers==0.0.5
+	pygments-github-lexers==0.0.5
 
 ssl =
-    wincertstore==0.2; sys_platform=='win32'
+	wincertstore==0.2; sys_platform=='win32'
 
 certs =
-    certifi==2016.9.26
+	certifi==2016.9.26
 
 [options.entry_points]
 
diff --git a/tox.ini b/tox.ini
index 8ab2b8cf02..aea213c4ec 100644
--- a/tox.ini
+++ b/tox.ini
@@ -53,7 +53,7 @@ commands =
 skip_install = True
 deps =
 	build
-	twine[keyring]>=1.13
+	twine>=3
 	path
 	jaraco.develop>=7.1
 	jaraco.tidelift