Add warning message

[jeevasusej]

Here I can find success and error but not warning.

1. Good to have warning type
2. Good to have header for error message
3. Good to implement close all error message if we have more than one
4. Good to pass additional values with success, warning, custom etc.. If we implement our own wrapper, This will be useful. Now I am sending additional params like

   toast.success('This is success message', {
     heading: 'Heading text',
   } as any);

toast('This is warning message', { type: 'warning' } as any);

[jack75015]

+1 for a REAL warning message :)

otherwise:

      toast("Warning", {
        icon: "⚠️",
      });

[huazhuangnan]

https://github.com/timolins/react-hot-toast/issues/29 @jeevasusej @jack75015