Files don't need individual license headers.

- All files are licensed by the LICENSE file at root.
- Updated the license to 2021.
- Have kept the license in LS_COLORS since its 3rd party.

install-dependencies

@@ -1,8 +1,5 @@
 #!/bin/bash
 
-# Copyright (C) 2015-2019 Andrew Hamilton. All rights reserved.
-# Licensed under the Artistic License 2.0.
-
 
 set -e