fix typo in systemd unit example

Signed-off-by: Mattia Rizzolo <mattia@debian.org>

deploy/README.md

@@ -63,7 +63,7 @@ Set up systemd units in `~/.config/systemd/user` for the deploy user:
 Path activation `deploy.path`:
 ```
 [Unit]
-Descriptor=Monitor <path to queue dir> for deployment requests
+Description=Monitor <path to queue dir> for deployment requests
 
 [Path]
 PathExistsGlob=<path to queue dir>/*.deploy