archivers/py-borgbackup: Allow build with py-msgpack 1.2.1
- Bump PORTREVISION for package change
Obtained from: https://github.com/borgbackup/borg/commit/2b93c83c179569d9aeb02c6aa387e5312590f505
https://github.com/borgbackup/borg/commit/8abdd3b8bf065dceecd52d2b22d92b3c407a7c1d