Update LICENSE
Copyright reflects update from here:
https://github.com/d3/d3.github.com/blob/master/LICENSE
diff --git a/LICENSE b/LICENSE
index 7e097d1..1bd1546 100644
--- a/LICENSE
+++ b/LICENSE
@@ -271,7 +271,7 @@
For D3's World 110m (spot-oa/ui/flow/world-110m.json):
========================================================================
-Copyright (c) 2014, Michael Bostock
+Copyright (c) 2014-2019, Michael Bostock
All rights reserved.
Redistribution and use in source and binary forms, with or without
