Update README.md (#29)

Author: yspolyakov

README.md

@@ -1,6 +1,6 @@
 # OpenFHE-NumPy
 
-[![License](https://img.shields.io/badge/License-BSD%203--Clause-blue.svg)](https://opensource.org/licenses/BSD-3-Clause)
+[![License](https://img.shields.io/badge/License-BSD%202--Clause-blue.svg)](https://opensource.org/licenses/BSD-2-Clause)
 [![Python Versions](https://img.shields.io/badge/python-3.10%2B-blue)](https://www.python.org/)
 [![OpenFHE Version](https://img.shields.io/badge/OpenFHE-1.4.0%2B-green)](https://github.com/openfheorg/openfhe-development)