docs: update references to old fastify-* modules (#74)

Author: Fdawgs

README.md

@@ -1,15 +1,15 @@
-# fastify-error
+# @fastify/error
 
 ![CI](https://github.com/fastify/fastify-error/workflows/CI/badge.svg)
-[![NPM version](https://img.shields.io/npm/v/fastify-error.svg?style=flat)](https://www.npmjs.com/package/fastify-error)
+[![NPM version](https://img.shields.io/npm/v/@fastify/error.svg?style=flat)](https://www.npmjs.com/package/@fastify/error)
 [![Known Vulnerabilities](https://snyk.io/test/github/fastify/fastify-error/badge.svg)](https://snyk.io/test/github/fastify/fastify-error)
 [![js-standard-style](https://img.shields.io/badge/code%20style-standard-brightgreen.svg?style=flat)](https://standardjs.com/)
 
 A small utility, used by Fastify itself, for generating consistent error objects across your codebase and plugins.
 
 ### Install
 ```
-npm i fastify-error
+npm i @fastify/error
 ```
 
 ### Usage
@@ -26,14 +26,14 @@ createError(code, message [, statusCode [, Base]])
 - `Base` (`Error`, optional) - The base error object that will be used. (eg `TypeError`, `RangeError`)
 
 ```js
-const createError = require('fastify-error')
+const createError = require('@fastify/error')
 const CustomError = createError('ERROR_CODE', 'message')
 console.log(new CustomError())
 ```
 
 How to use an interpolated string:
 ```js
-const createError = require('fastify-error')
+const createError = require('@fastify/error')
 const CustomError = createError('ERROR_CODE', 'Hello %s')
 console.log(new CustomError('world')) // error.message => 'Hello world'
 ```