add format check to validate

Fixes #64

Author: alexkrolick

src/scripts/validate.js

@@ -18,6 +18,7 @@ const useDefaultScripts = typeof validateScripts !== 'string'
 const scripts = useDefaultScripts
   ? {
       build: ifScript('build', 'npm run build --silent'),
+      format: precommit ? null : ifScript('format', 'npm run format --list-different'),
       lint: precommit ? null : ifScript('lint', 'npm run lint --silent'),
       test: precommit
         ? null