LICENSE: Update to match bitcoin.org

Will Binns · Will Binns · commit 1f035c6a4a70 · 2020-05-17T22:46:02.000+02:00
diff --git a/LICENSE b/LICENSE
@@ -1,5 +1,4 @@
-Copyright (c) 2009-2019 Bitcoin.org
-Copyright (c) 2019 Bitcoin Developer Documentation
+Copyright (c) 2019-2020 developer.bitcoin.org
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
