[glibmm] CI: Return to using ubuntu:rolling (22.04)

[Kjell Ahlstedt <kjellahl src gnome org>]

commit ed7d771f67145fdb8aab427d25313bfc43e1c5a4
Author: Kjell Ahlstedt <kjellahlstedt gmail com>
Date:   Fri Sep 2 17:03:01 2022 +0200

    CI: Return to using ubuntu:rolling (22.04)

 .gitlab-ci.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index ac51f290..01fdae8e 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -1,6 +1,6 @@
-# 2022-08-23: ubuntu:latest = 22.04, ubuntu:rolling = 22.04, ubuntu:devel = 22.10
+# 2022-09-02: ubuntu:latest = 22.04, ubuntu:rolling = 22.04, ubuntu:devel = 22.10
 # See https://hub.docker.com/_/ubuntu
-image: ubuntu:devel
+image: ubuntu:rolling
 
 stages:
   - deps