fix: publish as esm module, fixes #26

Author: EGOIST

package.json

@@ -8,10 +8,15 @@
   "files": [
     "dist"
   ],
-  "main": "./dist/index.js",
   "types": "./dist/index.d.ts",
+  "exports": {
+    ".": {
+      "import": "./dist/index.mjs",
+      "default": "./dist/index.js"
+    }
+  },
   "scripts": {
-    "build": "tsup src/index.ts --format cjs --dts",
+    "build": "tsup src/index.ts --format cjs,esm --dts",
     "test": "npm run build && uvu -r esbuild-register --ignore fixtures",
     "prepublishOnly": "npm run build"
   },