hook auth stopped working after 0.26

Here is what my webhook returns:

` { 'X-Hasura-Role': 'anon' }`

And the error I get:

```
{
  "errors": [
    {
      "path": "$",
      "error": "Invalid response from authorization hook: Error in $: expected [a], encountered Object",
      "code": "unexpected"
    }
  ]
}
```

This happens on all my queries, works fine on v0.25.