feat(deps): move pino to peerDependencies

[maxkoryukov]

Hello!

I tried to follow guides and articles from NodeJS team and contributors and moved the pino dependency to the peerDependencies section in package.json

[KodrAus]

Thanks for working on this @maxkoryukov! This looks good to me. I'm not sure if it's technically a breaking change, but since pino-seq doesn't work without pino anyways I think this is ok for us to release in a minor version.