[pre-commit.ci] pre-commit autoupdate

updates:
- [github.com/PyCQA/flake8: 3.9.2 → 4.0.1](PyCQA/flake8@3.9.2...4.0.1)

Author: pre-commit-ci[bot]

.pre-commit-config.yaml

@@ -7,7 +7,7 @@ repos:
     -   id: check-yaml
     -   id: debug-statements
 -   repo: https://github.com/PyCQA/flake8
-    rev: 3.9.2
+    rev: 4.0.1
     hooks:
     -   id: flake8
         exclude: ^docs/conf.py