[gnome-builder] flatpak: add flathub repo to list or sources

[Christian Hergert <chergert src gnome org>]

commit 594cada885dfc9049fa148966a98da455c645119
Author: Christian Hergert <chergert redhat com>
Date:   Fri Sep 15 14:44:53 2017 -0700

    flatpak: add flathub repo to list or sources
    
    This will help us pick up the KDE runtimes.

 plugins/flatpak/gbp-flatpak-application-addin.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/plugins/flatpak/gbp-flatpak-application-addin.c b/plugins/flatpak/gbp-flatpak-application-addin.c
index c755bf7..38c1a2d 100644
--- a/plugins/flatpak/gbp-flatpak-application-addin.c
+++ b/plugins/flatpak/gbp-flatpak-application-addin.c
@@ -84,6 +84,7 @@ enum {
 static GbpFlatpakApplicationAddin *instance;
 static guint signals [N_SIGNALS];
 static BuiltinFlatpakRepo builtin_flatpak_repos[] = {
+  { "flathub",       "https://flathub.org/repo/flathub.flatpakrepo"; },
   { "gnome",         "https://sdk.gnome.org/gnome.flatpakrepo"; },
   { "gnome-nightly", "https://sdk.gnome.org/gnome-nightly.flatpakrepo"; },
 };