Export GraphQLOptions type directly from apollo-server-express.

Directly export `GraphQLOptions` from the `apollo-server-express` (and
synonymously, `graphql-server-express`) main module, rather than exporting
it only from `./expressApollo`.

While the type would have still been available to someone using "connect"
middleware, this could yield less shake-win for connect developers who might be
tree-shaking, as they'd unnecessarily introduce the "express" middleware entry
points.

packages/apollo-server-express/src/expressApollo.ts

@@ -7,8 +7,6 @@ import {
 } from 'apollo-server-core';
 import * as GraphiQL from 'apollo-server-module-graphiql';
 
-export type GraphQLOptions = GraphQLOptions;
-
 export interface ExpressGraphQLOptionsFunction {
   (req?: express.Request, res?: express.Response):
     | GraphQLOptions

packages/apollo-server-express/src/index.ts

@@ -1,10 +1,14 @@
+// Expose types which can be used by both middleware flavors.
+export { GraphQLOptions } from 'apollo-server-core';
+
+// Express Middleware
 export {
   ExpressGraphQLOptionsFunction,
   ExpressHandler,
   ExpressGraphiQLOptionsFunction,
   graphqlExpress,
   graphiqlExpress,
-  GraphQLOptions,
 } from './expressApollo';
 
+// Connect Middleware
 export { graphqlConnect, graphiqlConnect } from './connectApollo';