refactor cp command

packages/hackmd/package.json

@@ -5,7 +5,7 @@
   "license": "MIT",
   "main": "dist/index.js",
   "scripts": {
-    "build": "vite build && cp ./src/index.js ./dist"
+    "build": "vite build && npx -y shx cp ./src/index.js ./dist"
   },
   "dependencies": {},
   "devDependencies": {