Update Unicode data to 15.1.0.

Change-Id: Ib7f114defaae0397f80463fcdaf8b2f9794fa8be
Reviewed-on: https://code-review.googlesource.com/c/re2/+/61930
Reviewed-by: Paul Wankadia <junyer@google.com>
Reviewed-by: Alex Chernyakhovsky <achernya@google.com>
3 files changed