fix: TypeError on different "graphql" versions

[dobrinov]

If there is a difference in the versions of "graphql" used by "apollo-link-scalars" and the project including it there might be difference in the structure of the schema instance created by makeExecutableSchema. This is the case with "graphql" 14.x and 15.x. and will result in a TypeError - "The types returned by 'getQueryType()' are incompatible between these types.".

To fix this I am exposing makeExecutableSchema through "apollo-link-scalars" to ensure that the types in the generated schema will be compatible by those expected from withScalars.

• What kind of change does this PR introduce? (Bug fix, feature, docs update, ...)
  Bug fix

• What is the current behavior? (You can also link to an open issue here)
  My project is using "graphql" version "15.3.0" and the one used by "apollo-link-scalars" is "14.5.8". I am getting the following TypeError:

app/javascript/gamma/utils/apollo.ts:47:29 - error TS2322: Type 'import(".../dev/.../application/node_modules/graphql/type/schema").GraphQLSchema' is not assignable to type 'import(".../dev/apollo-link-scalars/node_modules/graphql/type/schema").GraphQLSchema'.
  The types returned by 'getQueryType()' are incompatible between these types.
    Type 'Maybe<GraphQLObjectType<any, any>>' is not assignable to type 'Maybe<GraphQLObjectType<any, any, { [key: string]: any; }>>'.
      Type 'GraphQLObjectType<any, any>' is not assignable to type 'Maybe<GraphQLObjectType<any, any, { [key: string]: any; }>>'.
        Types of property 'isTypeOf' are incompatible.
          Type 'import("/Users/dobrinov/dev/receipt-bank/application/node_modules/graphql/jsutils/Maybe").Maybe<import(".../dev/receipt-bank/application/node_modules/graphql/type/definition").GraphQLIsTypeOfFn<any, any>>' is not assignable to type 'import("/Users/dobrinov/dev/apollo-link-scalars/node_modules/graphql/tsutils/Maybe").default<import(".../dev/apollo-link-scalars/node_modules/graphql/type/definition").GraphQLIsTypeOfFn<any, any>>'.
            Type 'GraphQLIsTypeOfFn<any, any>' is not assignable to type 'Maybe<GraphQLIsTypeOfFn<any, any>>'.
              Types of parameters 'info' and 'info' are incompatible.
                Type 'import(".../dev/apollo-link-scalars/node_modules/graphql/type/definition").GraphQLResolveInfo' is not assignable to type 'import(".../dev/receipt-bank/application/node_modules/graphql/type/definition").GraphQLResolveInfo'.
                  Types of property 'fieldNodes' are incompatible.
                    Type 'readonly import(".../dev/apollo-link-scalars/node_modules/graphql/language/ast").FieldNode[]' is not assignable to type 'readonly import(".../dev/.../application/node_modules/graphql/language/ast").FieldNode[]'.
                      Type 'import(".../dev/apollo-link-scalars/node_modules/graphql/language/ast").FieldNode' is not assignable to type 'import(".../dev/receipt-bank/.../node_modules/graphql/language/ast").FieldNode'.
                        Types of property 'loc' are incompatible.
                          Type 'import(".../dev/apollo-link-scalars/node_modules/graphql/language/ast").Location | undefined' is not assignable to type 'import(".../dev/.../application/node_modules/graphql/language/ast").Location | undefined'.
                            Property 'toJSON' is missing in type 'import(".../dev/apollo-link-scalars/node_modules/graphql/language/ast").Location' but required in type 'import(".../dev/receipt-bank/application/node_modules/graphql/language/ast").Location'.

• What is the new behavior (if this is a feature change)?
  n/a

• Other information:
  n/a

[dobrinov]

Actually after thinking more about this the right way to do this is to define graphql as "peerDependency". The implementation here will also work and will allow different graphql versions but the "peerDependency" solution is probably the more correct one.

Having a peer dependency means that your package needs a dependency that is the same exact dependency as the person installing your package. This is useful for packages like react that need to have a single copy of react-dom that is also used by the person installing it.

https://classic.yarnpkg.com/en/docs/dependency-types

[eturino]

I'll merge this PR and then look about moving it to a peer dependency @dobrinov
Thanks!

[eturino]

@all-contributors please add @dobrinov for bug and idea

[allcontributors]

@eturino

I've put up a pull request to add @dobrinov! 🎉