Add postgresql service to requirements

If this unit gets activated, the units listed in Requires= will be
activated as well. If one of the other units fails to activate, and an
ordering dependency After= on the failing unit is set, this unit will
not be started. Besides, with or without specifying After=, this unit
will be stopped (or restarted) if one of the other units is explicitly
stopped (or restarted).

Reference: https://progress.opensuse.org/issues/122578

systemd/openqa-webui.service

@@ -3,7 +3,7 @@ Description=The openQA web UI
 Wants=apache2.service openqa-setup-db.service
 Before=apache2.service
 After=postgresql.service openqa-setup-db.service openqa-scheduler.service nss-lookup.target remote-fs.target
-Requires=openqa-livehandler.service openqa-websockets.service openqa-gru.service openqa-enqueue-asset-cleanup.timer openqa-enqueue-result-cleanup.timer openqa-enqueue-bug-cleanup.timer
+Requires=openqa-livehandler.service openqa-websockets.service openqa-gru.service postgresql.service openqa-enqueue-asset-cleanup.timer openqa-enqueue-result-cleanup.timer openqa-enqueue-bug-cleanup.timer
 
 [Service]
 User=geekotest