chore: switch deprecated prettyPrint

[lmauromb]

Found the following message when trying to run npm run demo

throw new Error('prettyPrint option is no longer supported, see the pino-pretty package (https://github.com/pinojs/pino-pretty)')

As the error says the prettyPrint option is no longer supported and instead the recommendation is to use the pino-pretty package, which is already included.

This PR switch the options to use `pino-pretty.

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