[pre-commit.ci] pre-commit autoupdate (#201)

updates:
- [github.com/psf/black: 21.8b0 → 21.9b0](psf/black@21.8b0...21.9b0)
- [github.com/PyCQA/flake8: 3.9.2 → 4.0.1](PyCQA/flake8@3.9.2...4.0.1)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

.pre-commit-config.yaml

@@ -17,14 +17,14 @@ repos:
         # Don't commit to main branch.
     -   id: no-commit-to-branch
 -   repo: https://github.com/psf/black
-    rev: "21.8b0"
+    rev: "21.9b0"
     hooks:
     -   id: black
         # Force black to run on whole repo, using settings from pyproject.toml
         pass_filenames: false
         args: ["--config=./pyproject.toml", "--check", "."]
 -   repo: https://github.com/PyCQA/flake8
-    rev: "3.9.2"
+    rev: "4.0.1"
     hooks:
         # Run flake8.
     -   id: flake8