[pre-commit.ci] pre-commit autoupdate (#139)

updates:
- [github.com/psf/black: 21.6b0 → 21.7b0](psf/black@21.6b0...21.7b0)

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

.pre-commit-config.yaml

@@ -1,6 +1,6 @@
 repos:
 -   repo: https://github.com/psf/black
-    rev: 21.6b0
+    rev: 21.7b0
     hooks:
     - id: black
       args: [--line-length=99, --safe]