[epiphany/mcatanzaro/werror] Enable -Werror on the CI

[Michael Catanzaro <mcatanzaro src gnome org>]

commit e1b1e49e1c05b39ee715a97d9abe3266cea03e53
Author: Michael Catanzaro <mcatanzaro igalia com>
Date:   Fri Mar 1 20:27:04 2019 -0600

    Enable -Werror on the CI
    
    CI should not allow build warnings.

 .gitlab-ci.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index f08a3692d..6311fee63 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -11,7 +11,7 @@ flatpak:
     FLATPAK_MODULE: 'epiphany'
     # Make sure to keep this in sync with the Flatpak manifest, all arguments
     # are passed except the config-args because we build it ourselves
-    MESON_ARGS: '-Dunit_tests=enabled -Dnetwork_tests=enabled'
+    MESON_ARGS: '-Dunit_tests=enabled -Dnetwork_tests=enabled --werror=true'
     APP_ID: 'org.gnome.Epiphany'
 
 review: