refactor: expose the ESM build with debug

So that debug logs can be printed with vite:

```js
import { defineConfig } from 'vite'
import react from '@vitejs/plugin-react'

export default defineConfig({
  plugins: [react()],
  server: {
    port: 4000
  },
  resolve: {
    conditions: ["development"]
  }
})
```

Related: socketio/socket.io-client@781d753

package.json

@@ -15,6 +15,7 @@
   "exports": {
     "import": {
       "node": "./build/esm-debug/index.js",
+      "development": "./build/esm-debug/index.js",
       "default": "./build/esm/index.js"
     },
     "require": "./build/cjs/index.js"