[pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

setup.cfg

diff --git a/setup.cfg b/setup.cfg
index 834b3e8..1603c7d 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -8,7 +8,7 @@
 author = Anthony Sottile
 author_email = asottile@umich.edu
 license = MIT
-license_file = LICENSE
+license_files = LICENSE
 classifiers =
     License :: OSI Approved :: MIT License
     Programming Language :: Python :: 3