Fix package.json exports (#120)

Author: truemogician

package.json

@@ -11,6 +11,7 @@
   "main": "./dist/index.cjs",
   "types": "types.d.ts",
   "exports": {
+    "types": "types.d.ts",
     "require": "./dist/index.cjs",
     "import": "./src/index.js",
     "default": "./src/index.js"