[gxml] CI: added GObject Introspection in pipeline

[Daniel Espinosa Ortiz <despinosa src gnome org>]

commit 777db4d93415d9044bab9e71602d59b21c609919
Author: Daniel Espinosa <esodan gmail com>
Date:   Fri Mar 2 12:07:20 2018 -0600

    CI: added GObject Introspection in pipeline

 .gitlab-ci.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 547ecb3..fee3182 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -6,7 +6,7 @@ stages:
 
 before_script:
   - apt update
-  - apt-get install -y libxml2-dev libglib2.0-dev valac libgee-0.8-dev gettext meson
+  - apt-get install -y libxml2-dev libglib2.0-dev valac libgee-0.8-dev gettext gobject-introspection meson
 
 build-gxml:
   stage: build