[pre-commit.ci] pre-commit autoupdate

[pre-commit-ci[bot]]

updates:

• https://github.com/python/black → https://github.com/psf/black
• github.com/psf/black: 20.8b1 → 21.8b0
• https://gitlab.com/pycqa/flake8 → https://github.com/PyCQA/flake8
• github.com/PyCQA/flake8: 3.8.4 → 3.9.2
• github.com/pycqa/isort: 5.7.0 → 5.9.3