[retro-gtk] flatpak: Bump the SDK back from 3.26 to master

[Adrien Plazas <aplazas src gnome org>]

commit 57283fee6a53636e23fd8afbda143dea39f9520c
Author: Adrien Plazas <kekun plazas laposte net>
Date:   Sun Nov 12 09:44:54 2017 +0100

    flatpak: Bump the SDK back from 3.26 to master
    
    Meson 0.43.0 is now available on master.

 flatpak/org.gnome.Retro.DemoSamplesTest.json |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/flatpak/org.gnome.Retro.DemoSamplesTest.json b/flatpak/org.gnome.Retro.DemoSamplesTest.json
index 599095e..5e64f30 100644
--- a/flatpak/org.gnome.Retro.DemoSamplesTest.json
+++ b/flatpak/org.gnome.Retro.DemoSamplesTest.json
@@ -1,7 +1,7 @@
 {
     "app-id": "org.gnome.Retro.DemoSamplesTest",
     "runtime": "org.gnome.Platform",
-    "runtime-version": "3.26",
+    "runtime-version": "master",
     "sdk": "org.gnome.Sdk",
     "command": "retro-demo-samples-test",
     "tags": ["nightly"],