Switch from Webpacker to cssbundling-rails, upgrade Tailwind

package.json

@@ -5,14 +5,21 @@
     "@rails/actioncable": "^6.0.0",
     "@rails/ujs": "^6.0.0",
     "@rails/webpacker": "4.3.0",
-    "@tailwindcss/forms": "^0.2.1",
-    "autoprefixer": "^9",
-    "postcss": "^7",
-    "tailwindcss": "npm:@tailwindcss/postcss7-compat",
+    "@tailwindcss/forms": "^0.4.0",
+    "autoprefixer": "^10.4.2",
+    "postcss": "^8.4.6",
+    "postcss-flexbugs-fixes": "^5.0.2",
+    "postcss-import": "^14.0.2",
+    "postcss-nested": "^5.0.6",
+    "postcss-preset-env": "^7.3.1",
+    "tailwindcss": "^3.0.22",
     "turbolinks": "^5.2.0"
   },
   "version": "0.1.0",
   "devDependencies": {
     "webpack-dev-server": "^3.11.0"
+  },
+  "scripts": {
+    "build:css": "tailwindcss --postcss -i ./app/assets/stylesheets/application.tailwind.css -o ./app/assets/builds/application.css"
   }
 }