[gtk/gtk-3-24] (6 commits) ...Merge branch 'wip/hadess/portal-select-folders' into 'gtk-3-24'

[Matthias Clasen <matthiasc src gnome org>]

Summary of changes:

  7b1b3fa... colorpickerportal: Use convenience function to fetch uint (*)
  4c71bf7... colorpickerportal: Simplify portal version fetching (*)
  f70f2d7... colorpickerportal: Don't throw warnings on missing version (*)
  93ab478... Add portal version checking helper (*)
  35fec1c... filechoosernativeportal: Allowing selecting folder(s) (*)
  5e76507... Merge branch 'wip/hadess/portal-select-folders' into 'gtk-3

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