build: bump black version

.pre-commit-config.yaml

@@ -12,7 +12,7 @@ repos:
       - id: django-upgrade
         args: [--target-version, "2.2"]
   - repo: https://github.com/psf/black
-    rev: 20.8b1
+    rev: 21.10b0
     hooks:
       - id: black
         args: ['--target-version', 'py37', '--skip-string-normalization', '--line-length', '110']