db dump timer: change service type to simple

oneshot considers the service to be active after the main process exits.
This is not wanted here, removing the declaration makes the type default
to simple, which considers units to be active when the main process is
running.

files/nxy-db-dump.service

@@ -2,5 +2,4 @@
 Description=nxy database dump timer
 
 [Service]
-Type=oneshot
 ExecStart=/usr/bin/pg_dump -d nxy_prod -f %h/dump.sql