chore: pre-commit autoupdate (#212)

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

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

Author: pre-commit-ci[bot]

.pre-commit-config.yaml

@@ -1,6 +1,6 @@
 repos:
 - repo: https://github.com/psf/black
-  rev: 21.8b0
+  rev: 21.9b0
   hooks:
     - id: black
       language_version: python3