✨ feat: add treaty error shorthand option

[m1212e]

This option allows for simple usage of the treaty client. It offers a shouldThrow in the config which makes the client throw in case of an error instead of returning the whole response object.

This reduces the boilerplate in environments where throwing is desired and simplifies the response handling:

const userResult = await backend.auth["upsert-self"].post();
if (userResult.error) {
  throw userResult.error;
}
const user = userResult.data;

// becomes
const user = await backend.auth["upsert-self"].post();

This way the users can decide how the client should behave per default.
Let me hear what you think!

[kravetsone]

maybe just throw?

[m1212e]

You mean the field name of the config option?