Update Borg 2 beta links.

docs/how-to/make-per-application-backups.md

@@ -133,7 +133,7 @@ For Borg 1.x, use a shell pattern for the `match_archives` value and see the
 [Borg patterns
 documentation](https://borgbackup.readthedocs.io/en/stable/usage/help.html#borg-help-patterns)
 for more information. For Borg 2.x, see the [match archives
-documentation](https://borgbackup.readthedocs.io/en/2.0.0b8/usage/help.html#borg-help-match-archives).
+documentation](https://borgbackup.readthedocs.io/en/2.0.0b12/usage/help.html#borg-help-match-archives).
 
 Some borgmatic command-line actions also have a `--match-archives` flag that
 overrides both the auto-matching behavior and the `match_archives`

docs/how-to/upgrade.md

@@ -193,7 +193,7 @@ confirmation of success—or tells you if something hasn't been transferred yet.
 Note that by omitting the `--upgrader` flag, you can also do archive transfers
 between related Borg 2 repositories without upgrading, even down to individual
 archives. For more on that functionality, see the [Borg transfer
-documentation](https://borgbackup.readthedocs.io/en/2.0.0b8/usage/transfer.html).
+documentation](https://borgbackup.readthedocs.io/en/2.0.0b12/usage/transfer.html).
 
 That's it! Now you can use your new Borg 2 repository as normal with
 borgmatic. If you've got multiple repositories, repeat the above process for