Add pre-commit config

.pre-commit-config.yaml

@@ -0,0 +1,12 @@
+repos:
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v1.2.3
+    hooks:
+      - id: trailing-whitespace
+      - id: check-merge-conflict
+      - id: mixed-line-ending
+      - id: end-of-file-fixer
+  - repo: https://github.com/koalaman/shellcheck-precommit
+    rev: v0.10.0
+    hooks:
+      - id: shellcheck