[epiphany] Try to disable shallow clones

[Michael Catanzaro <mcatanzaro src gnome org>]

commit 3ae4bfa2ad5266e2f39a28358d67a3640d01a2a7
Author: Michael Catanzaro <mcatanzaro gnome org>
Date:   Fri Jul 31 13:58:38 2020 -0500

    Try to disable shallow clones
    
    Shallow clones break 'git describe', which breaks Tech Preview's about
    dialog. I like to be able to see exactly which commit I'm testing.
    
    https://gitlab.gnome.org/GNOME/epiphany/-/merge_requests/782#note_880152

 .gitlab-ci.yml | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index c83d7b23a..b43c9ec5e 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -6,6 +6,7 @@ variables:
   RUNTIME_REPO: 'https://nightly.gnome.org/gnome-nightly.flatpakrepo'
   FLATPAK_MODULE: 'epiphany'
   APP_ID: 'org.gnome.Epiphany.Devel'
+  GIT_DEPTH: '0'
 
 stages:
   - test