update to latest mach-core API

Signed-off-by: Stephen Gutekanst <stephen@hexops.com>

src/editor/main.zig

@@ -39,7 +39,7 @@ pub fn main() !void {
         defer app.deinit();
 
         while (true) {
-            if (try app.update()) return;
+            if (try app.core.internal.update(&app)) return;
         }
     }