Merge https://github.com/jaraco/skeleton

.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

pytest.ini

@@ -5,5 +5,3 @@ 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

setup.cfg

@@ -18,7 +18,7 @@ classifiers =
 	Programming Language :: Python :: 3 :: Only
 
 [options]
-packages = find:
+packages = find_namespace:
 include_package_data = true
 python_requires = >=3.6
 install_requires =
@@ -28,10 +28,17 @@ install_requires =
 	importlib_metadata >= 1; python_version < "3.8"
 setup_requires = setuptools_scm[toml] >= 3.4.1
 
+[options.packages.find]
+exclude =
+	build*
+	dist*
+	docs*
+	tests*
+
 [options.extras_require]
 testing =
 	# upstream
-	pytest >= 3.5, !=3.7.3
+	pytest >= 4.6
 	pytest-checkdocs >= 1.2.3
 	pytest-flake8
 	pytest-black >= 0.3.7; python_implementation != "PyPy"