[nautilus/testing-ci] Update .gitlab-ci.yml

[Carlos Soriano <csoriano src gnome org>]

commit 294eb1d38b9f641ddb1707214a8553c07e48ccd2
Author: Carlos Soriano <csoriano1618 gmail com>
Date:   Sun Mar 18 00:58:34 2018 +0000

    Update .gitlab-ci.yml

 .gitlab-ci.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index d27f59dd2..d198471c9 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -7,7 +7,7 @@ flatpak:master:
     stage: test
     script:
     # This should be removed once the base image works with git submodules
-    - dnf install -y git
+    - dnf install -y git tree
     - flatpak-builder --force-clean --keep-build-dirs --repo=repo app 
build-aux/flatpak/org.gnome.Nautilus.json
     # Make a Flatpak Nautilus bundle for people to test
     - flatpak build-bundle repo nautilus-dev.flatpak org.gnome.Nautilus