Update README.md with license information

We (01.AI) have updated our license from yi-license to apache-2.0. As part of this change, we kindly ask that all derivatives currently under the yi-license be updated to the apache-2.0 license as well. Thanks for your understanding and cooperation.

README.md

@@ -8,6 +8,5 @@ tags:
 - Yi-Ko
 - 01-ai
 - Yi
-license: other
-license_name: yi-license
+license: apache-2.0
 ---