fix(types): make definitions nodenext compatible

[cesarvspr]

Checklist

• run npm run test and npm run benchmark
• tests and/or benchmarks are included
• documentation is changed or added
• commit message and code follows the Developer's Certification of Origin
  and the Code of conduct

[climba03003]

Missing the update for index.js

fastify-multipart/index.js

Lines 578 to 581 in c486ecf

	module.exports = fp(fastifyMultipart, {
	fastify: '4.x',
	name: '@fastify/multipart'
	})

[mcollina]

lgtm