Feature Requests for warning and max toast

[yeasin-2002]

First of all, thanks for this awesome library. After knowing about his library, I literally stopped using other toasting libraries. But i feel something missing.
And that think is warning toast. i think it will be great if you add warning toast.

for example:

toast.warning("This is warning toast")

And also, I think it would be great if you could add an option to Max Toast.
For example:
Max: 3.
In that cause if i have 3 toast and i want to show another toast then it will remove the first toast and show the new toast.

Here it's creating a problem for me.