How can I declare a plugin schema than has table type field, which key can be any character

Questions
1

Hi, I can declare a plugin schema, like that:

    return {
      no_consumer = true,
      fields = {
     host_dict = {
      type = "table",
    }
    }

but, i want to add the plugin by admin api，like that：

curl -X POST http://localhost:8001/plugins -d '{"name":"plugin-name","config.host_dict":{"google.com":"value"}}'

what I want is set the key “a.b”, but the result is that:

{
    "host_dict": {
        "google": {
            "com": "value"
        }
    }
}

which is not what I want。
what I need is:

{
    "host_dict": {
        "google.com": "value"
    }
}

so my question is how to escape the char dot: ‘.’ ?

Thank You!