Reflect roman function correctly in the documentation

[erikjuhani]

Description

Change the value to correctly reflect the API. The API actually returns a value between 0 and 3999.

Zero is parsed as N, nil.

This change should be reflected for the package README as well.

- throw Error("only unsigned integer between range 1..3999 are supported");
+ throw Error("only unsigned integer between range 0..3999 are supported");

https://github.com/erikjuhani/umbrellajs/blob/main/packages/roman/src/roman.ts#L5