[gnome-calculator] Updated snap build base image

[Robert Roth <robertroth src gnome org>]

commit e08a69528b5688dc8e090d307bffc23989b6c4b4
Author: Robert Roth <robert roth off gmail com>
Date:   Thu Jun 4 13:51:16 2020 +0300

    Updated snap build base image

 .gitlab-ci.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 17c105ae..89ab4ca8 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -37,7 +37,7 @@ build:ubuntu:
 
 build:snap:
   stage: build
-  image: ubuntudesktop/gnome-3-28-1804
+  image: ubuntudesktop/gnome-3-34-1804
   before_script:
     - apt-get update
   script: snapcraft