"types" property required in package.json

It seems that it's not sufficient to add the following part to support types, yet:
```
"exports": {
    "types": "./dist/index.d.ts",
    "default": "./dist/index.js"
  },
```

I believe that you have to modify as follows in the `package.json`:
```
"main": "./dist/index.js",
"types": "./dist/index.d.ts",
```