Add support for aria-label/aria-labelledby and role in ToastContainer

[fabianherrera15]

First of all, thank you for this library and the effort put into making it accessible!
I'd like to see support for a role attribute that will be added to the ToastContainer element in conjunction with an aria-label or aria-labelledby, this will help screen reader users identifying this container as a landmark and facilitate navigation to it.
If implemented, the rendered element will look like this in the DOM for example<div role="complementary" aria-label="notifications" class="Toastify__toast-container">
The current workaround is to wrap the ToastContainer component with a div element that contains these attributes but ideally, we shouldn't bloat the DOM with more elements.

[fkhadra]

Hey @fabianherrera15 thanks for your feedback appreciate it. I'll consider adding that for the next release

[EGurney]

I would LOVE this. It would make testing also a bit easier, as React Testing Library really pushes towards using labels and whatnot (for good reason).