Fix broken backup_borg link

Referenced here: 06f5be4fa5 (r100414988)

CHANGELOG.md

@@ -4,7 +4,7 @@
 
 **TLDR**: the `matrix-backup-borg` role is now included from another repository. Some variables have been renamed. All functionality remains intact.
 
-Thanks to [moan0s](https://github.com/moan0s), the `matrix-backup-borg` role (which configures [Borg backups](docs/configuring-playbook-backup-borg.md)) has been extracted from the playbook and now lives in its [own repository](https://gitlab.com/etke.cc/roles/borg_backup). This makes it possible to easily use it in other Ansible playbooks and will become part of [nextcloud-docker-ansible-deploy](https://github.com/spantaleev/nextcloud-docker-ansible-deploy) soon.
+Thanks to [moan0s](https://github.com/moan0s), the `matrix-backup-borg` role (which configures [Borg backups](docs/configuring-playbook-backup-borg.md)) has been extracted from the playbook and now lives in its [own repository](https://gitlab.com/etke.cc/roles/backup_borg). This makes it possible to easily use it in other Ansible playbooks and will become part of [nextcloud-docker-ansible-deploy](https://github.com/spantaleev/nextcloud-docker-ansible-deploy) soon.
 
 You need to **update you roles** (`just roles` or `make roles`) regardless of whether you're enabling Borg backup functionality or not. If you're making use of Borg backups via this playbook, you will need to update variable references in your `vars.yml` file (`matrix_backup_borg_` -> `backup_borg_`).