[epiphany] flatpak: Add builddir=true to the main epiphany module

[Michael Catanzaro <mcatanzaro src gnome org>]

commit a1c02118a503d7977cf4fd40cefa21da2e45141d
Author: vanadiae <vanadiae35 gmail com>
Date:   Tue Jun 29 18:39:50 2021 +0200

    flatpak: Add builddir=true to the main epiphany module
    
    It places the artifacts in
    .var/app/org.gnome.Builder/cache/gnome-builder/flatpak-builder, where they can
    all easily be excluded from backups or nuked if necessary.

 org.gnome.Epiphany.json | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/org.gnome.Epiphany.json b/org.gnome.Epiphany.json
index f5d0f73a3..77993c115 100644
--- a/org.gnome.Epiphany.json
+++ b/org.gnome.Epiphany.json
@@ -115,6 +115,7 @@
         {
             "name" : "epiphany",
             "buildsystem" : "meson",
+            "builddir" : true,
             "config-opts" : [
                 "-Dtech_preview=true",
                 "-Dprofile=Devel"