Add graphql dependency to server integrations

[olistic]

Fixes #1225

[evans]

@olistic Thank you so much for the PR! It would be better if graphql is a peer dependency of the integrations, so that a single version of graphql can be installed for the full package. Something like this line would be incredible

[olistic]

@evans Ups! I misunderstood your comment. What about apollo-server-integration-testsuite? Do we want the peer dependency there as well?

[evans]

@olistic The integration testsuite is a private package to the repository, so it doesn't need the peerDeps. Thank you so much for the PR!

[abernix]

The graphql@14 package is still a release-candidate (also, on npm) and utilizes semver "pre-release" versioning. This means the version range defined here only meets a version of graphql that hasn't been released yet. While that may seem like a forward-thinking idea, I'd caution against doing this until compatibility has been verified since offering it as a "peer dependency" today seems like an endorsement for its use.