[gitg] flatpak: Update gtksourceview dependency

[Alberto Fanjul <albfan src gnome org>]

commit b975d3cee3b77dfddfa72f6e5805f5a2828361d0
Author: Alberto Fanjul <albertofanjul gmail com>
Date:   Wed Aug 7 00:45:57 2019 +0200

    flatpak: Update gtksourceview dependency

 org.gnome.gitgDevel.json | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)
---
diff --git a/org.gnome.gitgDevel.json b/org.gnome.gitgDevel.json
index bec28cea..c7ec486a 100644
--- a/org.gnome.gitgDevel.json
+++ b/org.gnome.gitgDevel.json
@@ -137,12 +137,11 @@
         },
         {
             "name" : "gtksourceview",
-            "config-opts" : [ "--disable-Werror" ],
+            "buildsystem" : "meson",
             "sources" : [
                 {
                     "type" : "git",
-                    "url" : "https://gitlab.gnome.org/GNOME/gtksourceview.git";,
-                    "tag" : "gtksourceview-4-2"
+                    "url" : "https://gitlab.gnome.org/GNOME/gtksourceview.git";
                 }
             ]
         },