message: fix: use setWindowOpenHandler
  on('new-window', (event,url)=>...) is deprecated in favour of setWindowOpenHandler.
  This fixes a potential future bug if (/when) the new-window event is removed.
diff: @@ -102,9 +102,9 @@ const createWindow = async () => {
  menuBuilder.buildMenu();
  // Open urls in the user's browser
  - mainWindow.webContents.on('new-window', (event, url) => {
  - event.preventDefault();
  - shell.openExternal(url);
  + mainWindow.webContents.setWindowOpenHandler(edata => {
  + shell.openExternal(edata.url);
  + return { action: 'deny' };
  });
  // Remove this if your app does not use auto updates
  