[gnome-builder] (24 commits) ...foundry: release proper transient stage

[Christian Hergert <chergert src gnome org>]

Summary of changes:

  7454df6... flatpak: add IpcFlatpakRepo abstraction (*)
  08f7083... flatpak: include warning about old flatpak (*)
  d45d2c1... test: test for beta version relying on beta version (*)
  fb510ed... flatpak: upgrade runtime if already installed (*)
  f19ada3... flatpak: discover installation for ref (*)
  f94076e... repo: update remote after adding it (*)
  abd189d... flatpak: test resolution of llvm12 beta (*)
  6f882df... flatpak: allow updating from peer when locating ref (*)
  006a55d... flatpak: dont require cache when resolving extension (*)
  f34aa66... flatpak: give access to FLATPAK_CONFIG_DIR (*)
  83efd5d... flatpak: provide --sdk-extension for extensions (*)
  6330bed... flatpak: wire up FLATPAK_CONFIG_DIR (*)
  421c724... foundry: add missing transient accessors (*)
  8e2ec93... flatpak: add stage to install SDK runtimes (*)
  f921afd... flatpak: update SDK runtimes along with dependencies (*)
  bcf4098... omnibar: use g_signal_connect_object() (*)
  5bcb3ae... flatpak: fix connection with NULL transfer object (*)
  c1d53b1... flatpak: include ref name in warning message (*)
  f799752... flatpak: add helper to get refs for sdk/platform (*)
  fbd934e... flatpak: use proper refs for sdk downloading (*)
  f2e1278... flatpak: create notification for transfer (*)
  b6155db... flatpak: always run sdk download (*)
  75d5b47... foundry: fix items-changed for removal of transient stage (*)
  43436f1... foundry: release proper transient stage (*)

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