[nautilus] CI: Install meson from pip

[Carlos Soriano <csoriano src gnome org>]

commit 816b8247f3147637d13b55446ee38d4470c0f225
Author: Carlos Soriano <csoriano1618 gmail com>
Date:   Tue Jan 2 10:41:46 2018 +0000

    CI: Install meson from pip
    
    We always need the latest one.

 .gitlab-ci.yml | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 41756a4c2..224dfcc0d 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -9,6 +9,7 @@ before_script:
                    gobject-introspection-devel gsettings-desktop-schemas-devel
                    libselinux-devel libxml2-devel tracker-devel
                    desktop-file-utils libgexiv2-devel
+  - pip install meson
 
 build-nautilus:
   stage: build