Update graphql to v14

[trevor-scheer]

This issue is to upgrade packages dependent on graphql-js to v14.

v14 offers some handy utility functions for validating types of nodes.
They'll be useful here: #625

[justinanastos]

In addition, graphql@^0.13.2 is a dependency. If the consumer has another version of graphql installed, such as 0.14.x, then when the cli parses a schema.json file, it will use 0.14.x and instanceof checks will fail because there's multiple versions of graphql.

I suggest making graphql a peerDependency and setting the version to >^0.13.2 || ^0.14.0.

[justinanastos]

☝️ This might require updating the tests to run on both versions, which seems like something we should do anyway.

[daggerjames]

#624

[Slessi]

#577

[stevenpetryk]

#648 as well. These just keep on rolling in, and for some reason people cannot find the original issue for it either.

[stevenpetryk]

@trevor-scheer I think this also encompasses #630.