doc: Update small error in LICENSE for npm

This corresponds to npm/npm@6051a69

Author: zkat

LICENSE

@@ -346,7 +346,7 @@ The externally maintained libraries used by Node.js are:
     Copyright (c) their respective copyright owners
     Licensed on their respective license terms
 
-    The npm public registry at https://registry.npmjs.com
+    The npm public registry at https://registry.npmjs.org
     and the npm website at https://www.npmjs.com
     Operated by npm, Inc.
     Use governed by terms published on https://www.npmjs.com