fix: point towards the CommonJS types

In order to fix the following issue:

> error TS1479: The current file is a CommonJS module whose imports will produce 'require' calls; however, the referenced file is an ECMAScript module and cannot be imported with 'require'. Consider writing a dynamic 'import("@socket.io/component-emitter")' call instead.
>
> 1 import { Emitter } from "@socket.io/component-emitter";

This problem was introduced in [1], when reworking the dual packaging.

Related: socketio/socket.io-parser#132

[1]: ba6b56d

Author: darrachequesne

package.json

@@ -14,7 +14,7 @@
   },
   "main": "./lib/cjs/index.js",
   "module": "./lib/esm/index.js",
-  "types": "./lib/esm/index.d.ts",
+  "types": "./lib/cjs/index.d.ts",
   "repository": {
     "type": "git",
     "url": "https://github.com/socketio/emitter.git"