Update configuration.md - update path due to recent install path change (#1581)

Since `&& cd listmonk` was added to the installation, this path is changed.

docs/docs/content/configuration.md

@@ -97,7 +97,7 @@ To use the default `uploads` folder:
 ```yml
   app:
     volumes:
-      - ./listmonk/uploads:/listmonk/uploads
+      - ./uploads:/listmonk/uploads
 ```