Merge pull request #512 from nschloe/pre-commit-ci-update-config

[pre-commit.ci] pre-commit autoupdate

Author: nschloe

.pre-commit-config.yaml

@@ -5,7 +5,7 @@ repos:
       - id: isort
 
   - repo: https://github.com/psf/black
-    rev: 21.8b0
+    rev: 21.9b0
     hooks:
       - id: black
         language_version: python3