fix: add types to exports (#110)

Fixes
[#208](#208).
Typescript 5.0 has a [new
moduleResolution](https://dev.to/ayc0/typescript-50-new-mode-bundler-esm-1jic)
called `bundler`. This expects the `types` field included in the
`exports` field which we did not have.

Author: yusinto

package.json

@@ -13,11 +13,12 @@
     "bindings"
   ],
   "exports": {
+    "types": "./lib/index.d.ts",
     "require": "./lib/cjs/index.js",
     "import": "./lib/esm/index.js"
   },
   "main": "./lib/cjs/index.js",
-  "types": "lib/index.d.ts",
+  "types": "./lib/index.d.ts",
   "files": [
     "lib",
     "src",