[pitivi] (15 commits) Non-fast-forward update to branch thiblahute/sdk3.30

[Thibault Saunier <tsaunier src gnome org>]

The branch 'thiblahute/sdk3.30' was changed in a way that was not a fast-forward update.
NOTE: This may cause problems for people pulling from the branch. For more information,
please see:

 https://wiki.gnome.org/Git/Help/NonFastForward

Commits removed from the branch:

  7d44e1c... ci: docker: Build against GNOME 3.30
  8cddefe... build: Update flatpak SDK and deps
  913f645... WIP
  f64f30a... ci: Add a target to update our flatpak repository

Commits added to the branch:

  f26ff31... medialibrary: Disable force-proxy option for image assets. (*)
  bd540b9... check: Error messages of GstPluginDependency checks changed (*)
  2f2a3bd... Update Polish translation (*)
  1c3ff4f... menu: Use GtkPopoverMenu instead of GtkMenu for primary men (*)
  2b115b7... Update Polish translation (*)
  beb3cce... timeline: Show vertical scrollbar only when needed (*)
  7e6690e... layer: Show video icon when empty (*)
  bb23628... Update Brazilian Portuguese translation (*)
  d105a04... Update Spanish translation (*)
  259469f... ci: docker: Build against GNOME 3.30
  7372f91... build: Update flatpak SDK and deps
  92fab20... WIP
  faa7c9d... ci: Add a target to update our flatpak repository
  2f8577b... flatpak: Allow '/' in branch names
  305b497... WIP

(*) This commit already existed in another branch; no separate mail sent