chore: update FluffyStuff/riichi-mahjong-tiles license

README.md

@@ -71,8 +71,8 @@ additional terms or conditions.
 
 This project uses modified
 [riichi-mahjong-tiles](https://github.com/FluffyStuff/riichi-mahjong-tiles)
-by [FluffyStuff](https://github.com/FluffyStuff), licensed
-under [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/).
+by [FluffyStuff](https://github.com/FluffyStuff) in
+[public domain/CC0 1.0 Universal](https://creativecommons.org/publicdomain/zero/1.0/).
 
 This project uses mahjong tiles by
 [Martin Persson](https://www.martinpersson.org/) which are free for personal

tilesets/FluffyStuff/LICENSE.md

@@ -1 +1 @@
-This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
+The work in this directory is in the public domain. For more information, visit https://creativecommons.org/publicdomain/zero/1.0/.

tilesets/FluffyStuff/README.md

@@ -2,7 +2,6 @@ riichi-mahjong-tiles
 ====================
 
 The data in this directory is based on the work done
-by [FluffyStuff](https://github.com/FluffyStuff), licensed under Creative
-Commons Attribution 4.0 International License.
+by [FluffyStuff](https://github.com/FluffyStuff) in public domain/CC0 1.0 Universal.
 
 The original repository: https://github.com/FluffyStuff/riichi-mahjong-tiles