README.md: Updates graphql-go/graphql features.

Subscription support: graphql-go/graphql#49 (comment)
Dataloading support: graphql-go/graphql#389
Concurrency support: graphql-go/graphql#389

README.md

@@ -13,7 +13,7 @@ See the [docs](https://gqlgen.com/) for a getting started guide.
 | Docs | [docs](https://gqlgen.com) & [examples](https://github.com/99designs/gqlgen/tree/master/example) | [examples](https://github.com/graph-gophers/graphql-go/tree/master/example/starwars) | [examples](https://github.com/graphql-go/graphql/tree/master/examples) | [examples](https://github.com/samsarahq/thunder/tree/master/example)|
 | Query | :+1: | :+1: | :+1: | :+1: |
 | Mutation | :+1: | :construction: [pr](https://github.com/graph-gophers/graphql-go/pull/182) | :+1: | :+1: |
-| Subscription | :+1: | :construction: [pr](https://github.com/graph-gophers/graphql-go/pull/132) | :no_entry: [is](https://github.com/graphql-go/graphql/issues/207) | :+1: |
+| Subscription | :+1: | :construction: [pr](https://github.com/graph-gophers/graphql-go/pull/132) | :+1: | :+1: |
 | Type Safety | :+1: | :+1: | :no_entry: | :+1: | 
 | Type Binding | :+1: | :construction: [pr](https://github.com/graph-gophers/graphql-go/pull/194) | :no_entry: | :+1: |
 | Embedding | :+1: | :construction: [pr](https://github.com/graphql-go/graphql/pull/274) | :no_entry: | :no_entry: |
@@ -23,8 +23,8 @@ See the [docs](https://gqlgen.com/) for a getting started guide.
 | Stitching gql | :clock1: [is](https://github.com/99designs/gqlgen/issues/5) | :no_entry: | :no_entry: | :no_entry: |
 | Opentracing | :+1: | :+1: | :no_entry: | :scissors:[pr](https://github.com/samsarahq/thunder/pull/77) |
 | Hooks for error logging | :+1: | :no_entry: | :no_entry: | :no_entry: |
-| Dataloading | :+1: | :+1: | :no_entry: | :warning: |
-| Concurrency | :+1: | :+1: | :no_entry: [pr](https://github.com/graphql-go/graphql/pull/132) | :+1: |
+| Dataloading | :+1: | :+1: | :+1: | :warning: |
+| Concurrency | :+1: | :+1: | :+1: | :+1: |
 | Custom errors & error.path | :+1: | :no_entry: [is](https://github.com/graphql-go/graphql/issues/259) | :no_entry: | :no_entry: |