refactor: replace manual pre-commit with a declarative, installable pre-commit hook via pre-commit.com

.pre-commit-config.yaml

@@ -0,0 +1,27 @@
+# See https://pre-commit.com for more information
+# See https://pre-commit.com/hooks.html for more hooks
+#
+# Install pre-commit itself:
+#   $ pip install pre-commit
+#     OR
+#   $ brew install pre-commit
+#
+# Update all pre-commit hooks to latest version:
+#   $ pre-commit autoupdate
+#
+# Install all default pre-commit hooks locally:
+#   $ pre-commit install
+#
+# Apply a given pre-commit hook to all files:
+#   $ pre-commit run --all-files <id>
+#
+# Apply all pre-commit hooks to all files:
+#   $ pre-commit run --all-files
+ci:
+  autoupdate_schedule: monthly
+  submodules: true
+repos:
+ - repo: https://github.com/google/keep-sorted
+   rev: c71803fd297b5736f3bfab1cfd84424ca52e961a  # frozen: v0.7.1
+   hooks:
+     - id: keep-sorted