Graphql-yoga: Support graphql-deduplicator out-of-the-box

[schickling]

graphql-deduplicator is a great library to optimize your GraphQL requests given your GraphQL client supports the feature (Apollo Client has built-in support).

I suggest supporting graphql-deduplicator out-of-the-box with Yoga when the ?deduplicate=1 query parameter is set like described in the readme.

Would be great if someone could create a PR for this. 🙌

[lfades]

Hi @schickling I'll be working on this.

[lfades]

This feature was added with #272, we can close it now @schickling