feat: extension support (#78)

pkg/download/engine/polyfill/webpack.config.js

@@ -0,0 +1,12 @@
+import path from "path";
+import { fileURLToPath } from "url";
+
+const __dirname = fileURLToPath(import.meta.url);
+
+export default {
+  entry: "./src/index.js",
+  output: {
+    filename: "index.js",
+    path: path.resolve(__dirname, "../out"),
+  },
+};