Add a commit message for pre-commit autoupdate

Author: Armavica

.pre-commit-config.yaml

@@ -1,6 +1,7 @@
 # https://pre-commit.com/
 ci:
     autoupdate_schedule: monthly
+    autoupdate_commit_msg: 'Update pre-commit hooks'
 exclude: 'xarray/datatree_.*'
 repos:
   - repo: https://github.com/pre-commit/pre-commit-hooks