[pre-commit.ci] pre-commit autoupdate (#307)
[pre-commit.ci] pre-commit autoupdate (#307)

updates:
- https://github.com/pre-commit/mirrors-isort → https://github.com/PyCQA/isort
- [github.com/PyCQA/isort: v5.8.0 → 5.9.1](https://github.com/PyCQA/isort/compare/v5.8.0...5.9.1)
- https://github.com/ambv/black → https://github.com/psf/black
- [github.com/psf/black: 21.5b2 → 21.6b0](https://github.com/psf/black/compare/21.5b2...21.6b0)
- [github.com/pre-commit/mirrors-mypy: v0.812 → v0.910](https://github.com/pre-commit/mirrors-mypy/compare/v0.812...v0.910)
- https://gitlab.com/pycqa/flake8 → https://github.com/PyCQA/flake8

Co-authored-by: pre-commit-ci[bot] <3ea08453efb076ca910552532a53973a6527df40@users.noreply.github.com>
hasgeek/coaster