[polari/ci] ci: Add missing dependency

[Gitlab System User <gitlab src gnome org>]

commit 9b2248a48ff36f1184ecd0e45b521fb30b57990e
Author: Florian Müllner <fmuellner gnome org>
Date:   Thu Oct 19 06:41:15 2017 +0200

    ci: Add missing dependency

 .gitlab-ci.yml | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index ac7603a..0e52a57 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -4,8 +4,9 @@ stages:
  - build
 
 before_script:
-  - dnf install -y gcc meson ninja-build redhat-rpm-config gettext gtk3-devel
-                   gjs-devel gobject-introspection-devel telepathy-glib-devel
+  - dnf install -y gcc meson ninja-build redhat-rpm-config gettext itstool
+                   gtk3-devel gjs-devel gobject-introspection-devel
+                   telepathy-glib-devel
 
 build-polari:
   stage: build