[ghex] CI: add nightly rule

[Logan Rathbone <larathbone src gnome org>]

commit de630dc01a37b4da9eef6b21f9cc09aa7f8ff17f
Author: Logan Rathbone <poprocks gmail com>
Date:   Sun Aug 15 22:08:49 2021 -0400

    CI: add nightly rule

 .gitlab-ci.yml | 5 +++++
 1 file changed, 5 insertions(+)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 7b75d33a..478a8e55 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -9,3 +9,8 @@ flatpak:
         APP_ID: "org.gnome.GHex"
         BUNDLE: "ghex-dev.flatpak"
     extends: .flatpak
+
+nightly:
+    extends: '.publish_nightly'
+    dependencies: ['flatpak']
+    needs: ['flatpak']