Fix: move index.d.ts alongside index.js main entry (#11)

Author: drwpow

package.json

@@ -5,7 +5,6 @@
   "type": "module",
   "main": "src/index.js",
   "module": "src/index.js",
-  "types": "types",
   "files": [
     "src",
     "types/index.d.ts"