Update fedora.md

Author: revnil

content/manuals/engine/install/fedora.md

@@ -85,7 +85,7 @@ your DNF repositories) and set up the repository.
 
 ```console
 $ sudo dnf -y install dnf-plugins-core
-$ sudo dnf-3 config-manager --add-repo {{% param "download-url-base" %}}/docker-ce.repo
+$ sudo dnf-3 config-manager addrepo --from-repofile={{% param "download-url-base" %}}/docker-ce.repo
 ```
 
 #### Install Docker Engine