Please unblock package greetd.

[ Reason ]
This is related to #1032914. I coordinated with the phog package
maintainer to fix the situation.

[ Impact ]
PAM configuration conflicts with phog's embedded version (in previous
version).

[ Tests ]
There are no upstream tests that cover this code.
I have no idea how to make autopkgtests for interactive graphical
programs yet, so none either.
I have manually tested it on my system, the phog maintainer too, and the
package has been in unstable for some time without complaint.

[ Risks ]
None I can see.

[ Checklist ]
   [X] all changes are documented in the d/changelog
   [X] I reviewed all changes and I approve them
   [X] attach debdiff against the package in testing

[ Other info ]
Thanks for all the hard work.

unblock greetd/0.9.0-3

\_o<

Unblocked.