Fixing resizing programmatically when resizable is false #370

- GTK3 manual recommends using gtk_widget_set_size_request() to resize
without geometry constaints.
- https://developer.gnome.org/gtk3/stable/GtkWindow.html#gtk-window-resize

shoes/native/gtk.c

@@ -664,7 +664,7 @@ void shoes_native_app_title(shoes_app *app, char *msg) {
 
 void shoes_native_app_resize_window(shoes_app *app) {
     if ((app->os.window != NULL) && (app->width > 0 && app->height > 0)) {
-        gtk_window_resize(GTK_WINDOW(app->os.window), app->width, app->height);
+        gtk_widget_set_size_request(GTK_WINDOW(app->os.window), app->width, app->height);
     }
 }