chore: upgrade ajv to the latest version 7 release

[nigelhanlon]

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

[mcollina]

please remove package-lock.

[climba03003]

Should this be landed until fastify support ajv@7?

[simoneb]

Should this be landed until fastify support ajv@7?

I don't think so, this can be used independently of fastify and the upgrade in fastify may be slow to come. Unless there are other reasons to delay this upgrade we should merge.

[climba03003]

I don't think so, this can be used independently of fastify and the upgrade in fastify may be slow to come. Unless there are other reasons to delay this upgrade we should merge.

Make sense. Then, it should be bumping a major release as it may break the usage when the user is still on ajv@6.

[simoneb]

I don't think it should be a major, ajv is internal to this library and if we've done the upgrade right there's not breaking change exposed to the user.

[climba03003]

After the research on how npm and yarn for dependencies resolution. They are smarter than I though. I have no more question about the version or delay of landing.

[simoneb]

@mcollina @jsumners this is ready for review

[jsumners]

LGTM