[gparted] Prevent tzdata install hang in GitLab CI Ubuntu image (!60)

[Curtis Gedak <gedakc src gnome org>]

commit 5fecdbfc963e20f970429f20db5dd39dbf30e97d
Author: Mike Fleetwood <mike fleetwood googlemail com>
Date:   Fri May 22 15:59:35 2020 +0100

    Prevent tzdata install hang in GitLab CI Ubuntu image (!60)
    
    The Ubuntu based GitLab CI jobs have recently started being terminated
    after the default 1 hour timeout.  Installing / updating packages in the
    image is updating the tzdata package which is prompting for input which
    it will never receive, hence the hang.  The end of output from the job
    looks like this:
    
        Setting up tzdata (2020a-0ubuntu0.20.04) ...
        debconf: unable to initialize frontend: Dialog
        debconf: (TERM is not set, so the dialog frontend is not usable.)
        debconf: falling back to frontend: Readline
        Configuring tzdata
        ------------------
        Please select the geographic area in which you live. Subsequent configuration
        questions will narrow this down by presenting a list of cities, representing
        the time zones in which they are located.
          1. Africa      4. Australia  7. Atlantic  10. Pacific  13. Etc
          2. America     5. Arctic     8. Europe    11. SystemV
          3. Antarctica  6. Asia       9. Indian    12. US
        Geographic area:
        ...
        ERROR: Job failed: execution took longer than 1h0m0s seconds
    
    This is a well known issue [1][2][3].  Probably occurring now because of
    a new release of tzdata not included in the base Ubuntu image we are
    using.  Fix by telling the underlying dpkg tools this installation is
    non-interactive.
    
    [1] Avoiding user interaction with tzdata when installing certbot in a
        docker container
        
https://askubuntu.com/questions/909277/avoiding-user-interaction-with-tzdata-when-installing-certbot-in-a-docker-contai
    [2] How to install tzdata on a ubuntu docker image?
        https://serverfault.com/questions/949991/how-to-install-tzdata-on-a-ubuntu-docker-image
    [3] apt-get install tzdata noninteractive
        https://stackoverflow.com/questions/44331836/apt-get-install-tzdata-noninteractive
    
    Closes !60 - Fix GitLab CI job failures following Ubuntu docker image
                 updates

 .gitlab-ci.yml | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index d5754991..84df0f44 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -23,6 +23,7 @@ stages:
   # Use official Ubuntu image https://hub.docker.com/_/ubuntu/.
   image: ubuntu:latest
   before_script:
+    - export DEBIAN_FRONTEND=noninteractive
     - apt-get update
     - apt-get install -y gnome-common yelp-tools libglib2.0-dev-bin
                          uuid-dev libparted-dev libgtkmm-3.0-dev make