Add pyproject.toml as per PEP 518

.isort.cfg

@@ -1,6 +0,0 @@
-[settings]
-multi_line_output=3
-include_trailing_comma=True
-force_grid_wrap=0
-use_parentheses=True
-line_length=88

MANIFEST.in

@@ -1,6 +1,6 @@
 recursive-include docs *
 recursive-include tests *
-include pytest.ini tox.ini .isort.cfg .coveragerc *.md LICENSE AUTHORS
+include pyproject.toml pytest.ini tox.ini .coveragerc *.md LICENSE AUTHORS
 prune docs/_build
 prune *.pyc
 prune __pycache__

pyproject.toml

@@ -0,0 +1,7 @@
+[tool.isort]
+force_grid_wrap = 0
+include_trailing_comma = true
+line_length = 88
+multi_line_output = 3
+use_parentheses = true
+