Updating for v10

[Ranieri93]

Hello everyone!
I would like to work on this, as needed in issue #1762 and referenced here.

I guess here we don't need much explanation about the need for the update.
I should also mention that there is a dependency with pino-std-serializers, so I guess I'll work on that too.

@jsumners

[jsumners]

Thanks. I have created next branches here, in the koa module repo, and the standard serializers repo. Luckily, the standard serializers module is simple; it will probably only need some CI changes to eliminate old Node.js versions and some dependency bumps.

[mcollina]

v10 shipped