[libdmapsharing] .gitlab-ci.yml: select 32-bit image and set DEBIAN_FRONTEND=noninteractive

[W. Michael Petullo <wmpetullo src gnome org>]

commit 79d689e9875ebab03ff2d9ad0566a0e8500e9c88
Author: W. Michael Petullo <mike flyn org>
Date:   Tue Jun 30 18:44:22 2020 -0500

    .gitlab-ci.yml: select 32-bit image and set DEBIAN_FRONTEND=noninteractive

 .gitlab-ci.yml | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 140f233..847714d 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -1,5 +1,8 @@
 build-ubuntu:
-  image: ubuntu:rolling
+  image: i386/ubuntu:rolling
+
+  variables:
+    DEBIAN_FRONTEND: noninteractive
 
   before_script:
     - apt-get update