prepare release 2025-06-26

Blindly following https://code-review.googlesource.com/c/re2/+/63450.

Change-Id: I5cb128581275f4a4617a59eac76b9416e0166943
Reviewed-on: https://code-review.googlesource.com/c/re2/+/63590
Reviewed-by: Alan Donovan <adonovan@google.com>
2 files changed