[gnome-builder] meson-templates: use master for template

[Christian Hergert <chergert src gnome org>]

commit b25aa27220f365bbd547cf4fb5847fca393c3a1d
Author: Christian Hergert <chergert redhat com>
Date:   Wed Mar 3 22:07:30 2021 -0800

    meson-templates: use master for template
    
    We can change this once things have been released, but its nice to keep
    it pinned to the same version as GNOME Builder itself.

 src/plugins/meson-templates/resources/flatpak.json | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/plugins/meson-templates/resources/flatpak.json 
b/src/plugins/meson-templates/resources/flatpak.json
index 1bc2d1043..6e81ed8d3 100644
--- a/src/plugins/meson-templates/resources/flatpak.json
+++ b/src/plugins/meson-templates/resources/flatpak.json
@@ -1,7 +1,7 @@
 {
     "app-id" : "{{appid}}",
     "runtime" : "org.gnome.Platform",
-    "runtime-version" : "3.38",
+    "runtime-version" : "master",
     "sdk" : "org.gnome.Sdk",
 {{if language == "rust"}}
     "sdk-extensions" : [