[fractal] flatpak: Add builddir: true to manifest

[Daniel Garcia Moreno <danigm src gnome org>]

commit 42e1d50fb1de2b1ecbffa36dc3259a44270a1641
Author: Christopher Davis <brainblasted disroot org>
Date:   Mon Apr 22 12:46:54 2019 -0400

    flatpak: Add builddir: true to manifest
    
    GNOME Builder carries a re-implementation of flatpak-builder.
    flatpak-builder assumes that builddir is true for meson, but
    Builder does not since it also supports out-of-tree builds.
    
    This helps indicate to Builder that builddir can indeed be used.

 flatpak/org.gnome.Fractal.json | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/flatpak/org.gnome.Fractal.json b/flatpak/org.gnome.Fractal.json
index 3a430cbf..6d28edce 100644
--- a/flatpak/org.gnome.Fractal.json
+++ b/flatpak/org.gnome.Fractal.json
@@ -96,6 +96,7 @@
         {
             "name" : "fractal",
             "buildsystem" : "meson",
+            "builddir" : true,
             "config-opts" : [
                 "-Dprofile=development"
             ],