[gnome-builder] Use C++14 std::make_unique<> to instantiate Gtk::Window object

[Christian Hergert <chergert src gnome org>]

commit e8c28289b6197fe32e36031e07c9f8e0d516977a
Author: Keyikedalube Ndang <keyikedalubendang protonmail ch>
Date:   Fri Sep 4 07:22:53 2020 +0530

    Use C++14 std::make_unique<> to instantiate Gtk::Window object

 src/plugins/meson-templates/resources/src/main.cpp | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
---
diff --git a/src/plugins/meson-templates/resources/src/main.cpp 
b/src/plugins/meson-templates/resources/src/main.cpp
index f8ae8aed6..f17ff4d89 100644
--- a/src/plugins/meson-templates/resources/src/main.cpp
+++ b/src/plugins/meson-templates/resources/src/main.cpp
@@ -1,15 +1,16 @@
 {{include "license.cpp"}}
 
 #include "{{prefix}}-window.h"
+#include <memory>
 
 static void
 on_activate (Glib::RefPtr<Gtk::Application> app)
 {
        // Get the current window. If there is not one, we will create it.
-       Gtk::Window *window = app->get_active_window();
+       static std::unique_ptr<Gtk::Window> window;
 
        if (!window) {
-               window = new {{Prefix}}Window();
+               window = std::make_unique<{{Prefix}}Window>();
                window->property_application() = app;
                window->property_default_width() = 600;
                window->property_default_height() = 300;