Add rollup package

Author: yoktav

package.json

@@ -2,9 +2,12 @@
     "name": "twig-unused-css-finder",
     "version": "0.1.0",
     "description": "A tool to find unused CSS in Twig templates",
-    "main": "index.js",
+    "main": "dist/bundle.js",
+    "types": "dist/index.d.ts",
     "scripts": {
-      "start": "node index.js",
+      "build": "rollup -c",
+      "start": "node dist/bundle.js",
+      "dev": "rollup -c -w",
       "test": "echo \"Error: no test specified\" && exit 1"
     },
     "keywords": ["twig", "css", "unused", "finder"],
@@ -18,7 +21,11 @@
       "node": ">=14.0.0"
     },
     "devDependencies": {
+      "@rollup/plugin-commonjs": "^22.0.0",
+      "@rollup/plugin-node-resolve": "^13.3.0",
+      "@rollup/plugin-typescript": "^8.3.2",
       "@types/node": "^14.14.31",
+      "rollup": "^2.75.0",
       "tslib": "^2.4.0",
       "typescript": "^4.2.2"
     },