chore(rollup): output size snapshot of esm build

[emmenko]

To provide useful information about the bundle size, treeshaking, etc.

[emmenko]

This should help us improving treeshaking support, by looking at those numbers (current values below). I still don't know exactly what they mean by that what we should be looking at.

"treeshaked": {
  "rollup": {
    "code": 321329,
    "import_statements": 1038
  },
  "webpack": {
    "code": 343714
  }
}

[emmenko]

Also, interesting point here: remix-run/react-router#6464 (comment)

Basically, avoid using classes and use hooks instead 😅

[emmenko]

Closing this for now, as it currently fails because of this problem: TrySound/rollup-plugin-size-snapshot#24