[pre-commit.ci] pre-commit autoupdate (#21)

updates:
- [github.com/psf/black: 21.7b0 → 21.8b0](psf/black@21.7b0...21.8b0)

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

@@ -9,6 +9,6 @@ repos:
     -   id: check-yaml
     -   id: check-added-large-files
 -   repo: https://github.com/psf/black
-    rev: 21.7b0
+    rev: 21.8b0
     hooks:
     -   id: black