data: Fix display-manager service name

display-manager.target doesn't exist, but display-manager.service does.
That's the one we want to start before.

Closes: #21
Fixes: 3592c1c4
1 job for wip/hadess/fix-before-service in 1 minute and 32 seconds (queued for 1 second)
latest
Status Name Job ID Coverage
  Test
passed build #8905347

00:01:32