gtk-demo: Make some columns resizable

Make the columns in the List > Settings demo
resizable, to demonstrate this functionality.
9 jobs for columnview-resizing in 101 minutes and 45 seconds (queued for 2 seconds)
latest
Status Job ID Name Coverage
  .Pre
failed #750632
allowed to fail
style-check-diff

00:07:04

 
  Build
passed #750633
fedora-x86_64

00:16:46

passed #750635
win32-ps
msys2-mingw32

00:11:12

passed #750634
release-build

00:21:01

 
  Analysis
failed #750636
allowed to fail
static-scan

01:00:01

 
  Docs
passed #750637
reference

00:13:37

 
  Flatpak
manual #750638
flatpak allowed to fail manual
flatpak-manual:demo
manual #750640
flatpak allowed to fail manual
flatpak-manual:icon-browser
manual #750639
flatpak allowed to fail manual
flatpak-manual:widget-factory
 
Name Stage Failure
failed
static-scan Analysis The script exceeded the maximum execution time set for the job
      ^         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
3 warnings generated.
Running after_script
WARNING: Failed to inspect build container bf248fc94a6d9d25ac052b9aca27ba77f9af4826c174e7bc613afb4cd526b9e6 context deadline exceeded (docker_command.go:78:0s)
Authenticating with credentials from job payload (GitLab Registry)
Pulling docker image registry.gitlab.gnome.org/gnome/gtk/fedora:v16 ...
Uploading artifacts for failed job
Pulling docker image gitlab/gitlab-runner-helper:x86_64-c127439c ...
ERROR: Job failed: execution took longer than 1h0m0s seconds
failed
style-check-diff .Pre
 GtkListItemWidget *     gtk_column_view_get_header_widget       (GtkColumnView          *self);
-GtkListView * gtk_column_view_get_list_view (GtkColumnView *self);
+GtkListView *gtk_column_view_get_list_view (GtkColumnView *self);

void gtk_column_view_measure_across (GtkColumnView *self,
int *minimum,
Running after_script
Uploading artifacts for failed job
ERROR: Job failed: exit code 1