Remove year from LICENSE

Replicates graphql/graphql-js@8c96dc8

Author: Cito

LICENSE

@@ -1,8 +1,8 @@
 MIT License
 
-Copyright (c) 2017-2019 Facebook, Inc. (GraphQL.js)
-Copyright (c) 2016-2017 Syrus Akbary (GraphQL-core)
-Copyright (c) 2018-2019 Christoph Zwerschke (GraphQL-core-next)
+Copyright (c) Facebook, Inc. and its affiliates (GraphQL.js)
+Copyright (c) Syrus Akbary (GraphQL-core)
+Copyright (c) Christoph Zwerschke (GraphQL-core-next)
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal