Support graphql@16 by fixing dependency on apollo-graphql

[sushantdhiman]

As per #5605 graphql@16 should already be supported but it doesn't look like this.

apollo-server-core@3.5.0 currently dependent upon apollo-graphql@0.9.5 which still requires graphql@15 or below

npm WARN Could not resolve dependency:
npm WARN peer graphql@"^14.2.1 || ^15.0.0" from apollo-graphql@0.9.5
npm WARN node_modules/apollo-server-core/node_modules/apollo-graphql
npm WARN   apollo-graphql@"^0.9.0" from apollo-server-core@3.5.0
npm WARN   node_modules/apollo-server-core

To properly complete support for graphql@16

• Support graphql@16 for apollo-graphql (I don't know where this repo exists)
• Release apollo-server-core with fixed version of apollo-graphql

[glasser]

Good point. The best thing to do here is probably just to inline the small amount of code in apollo-graphql that apollo-server-core and apollo-server-plugin-operation-registry use directly into this repo and drop the dependency rather than do more releases of that package. There's no particularly good reason for "the usage reporting specific signature algorithm" and "the operation registry specific signature algorithm" to live far away from the usage reporter and the operation registry plugin.

[glasser]

(I will also say that while I do see the problem here, I'm confused as to why others haven't run into this yet... surely you are not the first person trying to combine the release of AS3 that is supposed to support graphql@16 with graphql@16...)