Merge pull request #1252 from jupyterhub/pre-commit-ci-update-config

[pre-commit.ci] pre-commit autoupdate

Author: minrk

.pre-commit-config.yaml

@@ -44,7 +44,7 @@ repos:
 
   # Autoformat: markdown
   - repo: https://github.com/pre-commit/mirrors-prettier
-    rev: v3.0.0-alpha.4
+    rev: v3.0.0-alpha.6
     hooks:
       - id: prettier
         files: ".md"