implement autoprefixer & cssnano with postcss

assets/package.json

@@ -11,6 +11,8 @@
   "devDependencies": {
     "@types/node": "^18.6.5",
     "@types/phoenix": "^1.5.4",
+    "autoprefixer": "^10.4.13",
+    "cssnano": "^5.1.14",
     "phoenix_live_view": "^0.18.11",
     "sass": "^1.54.3",
     "vite": "^4.0.4"

assets/postcss.config.cjs

@@ -0,0 +1,5 @@
+module.exports = {
+  plugins: [require("autoprefixer"),require('cssnano')({
+    preset: 'default',
+  })],
+};