initial pre-commit config

soft launch meaning only people with pre-commit tool installed would
see this run.  If you want to see full effect on files run:
`pre-commit run --all-files`

fixes riscv-software-src#260

.pre-commit-config.yaml

@@ -0,0 +1,20 @@
+---
+repos:
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v5.0.0
+    hooks:
+      - id: check-symlinks
+      - id: check-yaml
+      - id: end-of-file-fixer
+      - id: trailing-whitespace
+        args: [--markdown-linebreak-ext=md]
+
+  - repo: https://github.com/rbubley/mirrors-prettier
+    rev: v3.3.3
+    hooks:
+      - id: prettier
+
+  - repo: https://github.com/rhysd/actionlint
+    rev: v1.7.4
+    hooks:
+      - id: actionlint