Add pre-commit hooks

Author: DimitriPapadopoulos

.pre-commit-config.yaml

@@ -0,0 +1,12 @@
+ci:
+  autoupdate_schedule: monthly
+
+exclude: ^(CNAME|assets|bibutils|_collections/_biblio|_sass)
+
+repos:
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v5.0.0
+    hooks:
+    - id: end-of-file-fixer
+    - id: mixed-line-ending
+    - id: trailing-whitespace