Fix link to backup administration intructions

Signed-off-by: Paulo Pires <[email protected]>

README.md

@@ -183,7 +183,7 @@ container — a container with a script which makes backups of the `default`
 blob store and then uploads them on a Google Cloud Storage bucket alongside the
 data generated by Nexus built-in backup task. These backups are triggered by
 a Nexus task of type _Execute script_ (to be configured as described in
-[`docs/admin/configuring-nexus.md`](docs/admin/configuring-nexus.md#configure-backup)).
+[`docs/admin/configuring-nexus.md`](docs/admin/configuring-nexus.md#configure-backup-tasks-and-create-backup-scripts)).
 The script reacts to changes made to
 
 ```