[gnome-flashback] ci: add libsystemd-dev

[Alberts Muktupāvels <muktupavels src gnome org>]

commit 15e7c2141b30b4620c969522c237b2231edeeb65
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Mon Nov 11 22:15:57 2019 +0200

    ci: add libsystemd-dev

 .gitlab-ci.yml | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index ae86b5e..e8020f9 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -29,6 +29,7 @@ build-ubuntu:
                       libpolkit-agent-1-dev
                       libpolkit-gobject-1-dev
                       libpulse-dev
+                      libsystemd-dev
                       libtool
                       libupower-glib-dev
                       libx11-dev