Upgrade black used by blacken-docs (#364)

adamchainz · web-flow · commit e3bb78707370 · 2021-09-21T14:06:24.000+01:00
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
@@ -24,7 +24,7 @@ repos:
   hooks:
   - id: blacken-docs
     additional_dependencies:
-    - black==21.7b0
+    - black==21.9b0
 - repo: https://github.com/pycqa/isort
   rev: 5.9.3
   hooks:
