Get rid of setup.cfg

I don't mind having a pytest.ini and I know I could fold it into tox.ini.
I just don't want to have two general purpose config files.

.pre-commit-config.yaml

@@ -23,6 +23,7 @@ repos:
     rev: v4.3.21
     hooks:
       - id: isort
+        additional_dependencies: [toml]
         language_version: python3.7
 
   - repo: https://github.com/pre-commit/pre-commit-hooks

MANIFEST.in

@@ -1,4 +1,4 @@
-include LICENSE *.rst *.toml *.yml *.yaml
+include LICENSE *.rst *.toml *.yml *.yaml *.ini
 graft .github
 
 # Stubs

pyproject.toml

@@ -7,6 +7,20 @@ build-backend = "setuptools.build_meta"
 line-length = 79
 
 
+[tool.isort]
+atomic=true
+force_grid_wrap=0
+include_trailing_comma=true
+lines_after_imports=2
+lines_between_types=1
+multi_line_output=3
+not_skip="__init__.py"
+use_parentheses=true
+
+known_first_party="attr"
+known_third_party=["attr", "hypothesis", "pytest", "setuptools", "six", "zope"]
+
+
 [tool.towncrier]
     package = "attr"
     package_dir = "src"

pytest.ini

@@ -0,0 +1,7 @@
+[tool:pytest]
+strict = true
+addopts = -ra
+testpaths = tests
+filterwarnings =
+    once::Warning
+    ignore:::pympler[.*]

setup.cfg

@@ -1,22 +0,0 @@
-[tool:pytest]
-minversion = 3.0
-strict = true
-addopts = -ra
-testpaths = tests
-filterwarnings =
-    once::Warning
-    ignore:::pympler[.*]
-
-
-[isort]
-atomic=true
-force_grid_wrap=0
-include_trailing_comma=true
-lines_after_imports=2
-lines_between_types=1
-multi_line_output=3
-not_skip=__init__.py
-use_parentheses=true
-
-known_first_party=attr
-known_third_party=hypothesis,pytest,setuptools,six,zope