Update README.md

Author: glassnotes

README.md

@@ -5,3 +5,14 @@ differentiable quantum transforms" [(arXiv)](https://arxiv.org/abs/2202.13414).
 
 To run the examples, first install the packages in the `requirements.txt`
 file. These examples were most recently tested with PennyLane version 0.29.1.
+
+---------------
+
+This work is licensed under a
+[Creative Commons Attribution 4.0 International License][cc-by].
+
+[![CC BY 4.0][cc-by-image]][cc-by]
+
+[cc-by]: http://creativecommons.org/licenses/by/4.0/
+[cc-by-image]: https://i.creativecommons.org/l/by/4.0/88x31.png
+[cc-by-shield]: https://img.shields.io/badge/License-CC%20BY%204.0-lightgrey.svg