remove 'About This App (modal with options)' item from example

because it is broken. The inner window created by clicking the item is
not closable. In addition, parent window is not closable when inner
window is open. So entire application window is not closable and only
Cmd+Q can close it.

example/main.js

@@ -18,20 +18,6 @@ app.once('ready', function() {
     });
     w.loadURL('file://' + join(__dirname, 'index.html'));
 
-    const options = {
-        icon_path: join(__dirname, 'icon.png'),
-        copyright: 'Copyright (c) 2015 rhysd',
-        package_json_dir: __dirname,
-        win_options: {
-            resizable: false,
-            minimizable: false,
-            maximizable: false,
-            movable: false,
-            parent: w,
-            modal: true,
-        }
-    }
-
     const menu = Menu.buildFromTemplate([
         {
             label: 'Example',
@@ -57,14 +43,9 @@ app.once('ready', function() {
                                 parent: w,
                                 modal: true,
                             },
-                            show_close_button: "Close"
+                            show_close_button: 'Close',
                         }),
                 },
-                {
-                    label: 'About This App (modal with options)',
-                    click: () =>
-                        openAboutWindow(options),
-                },
             ],
         },
     ]);