Deprecation warning description in README.md in `fastify.listen`

[phasetr]

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Issue

In the newest README.md, we have a description fastify.listen(3000, err => {, but this leads a deprecation warning, like

FastifyDeprecation: Variadic listen method is deprecated. Please use ".listen(optionsObject)" instead. The variadic signature will be removed in fastify@5.

This should be fastify.listen({ port: 3000 }, err => {.

[mcollina]

Thanks for reporting! Would you like to send a Pull Request to address this issue?

[phasetr]

The pull request is merged.