Fix incorrect version in documentation (#557).

docs/how-to/set-up-backups.md

@@ -197,7 +197,7 @@ command like the following with Borg 1.x:
 sudo borgmatic init --encryption repokey
 ```
 
-<span class="minilink minilink-addedin">New in borgmatic version 2.0.0</span>
+<span class="minilink minilink-addedin">New in borgmatic version 1.7.0</span>
 Or, with Borg 2.x:
 
 ```bash