Support constraintsBlock for showToast method

[audrl1010]

Hello there! I am a dedicated user of this library :)

The current custom toast view layout in the library is processed based on frames. Thus, when the toast is positioned at the bottom of the screen, there might be an issue where part of it gets clipped if the height of the toast's superview changes.

To prevent this situation, it would be beneficial to delegate the toast layout task in a callback format, enabling the use of flexible positioning methods such as auto-layout.

Here's an example of how this can be implemented.

let customToast = ....
self.view.showToast(customToast, constraints: { container, toast in
	toast.translatesAutoresizingMaskIntoConstraints = false
	toast.leftAnchor.constraint(equalTo: container.leftAnchor, constant: 20).isActive = true
	toast.rightAnchor.constraint(equalTo: container.rightAnchor, constant: -20).isActive = true
	toast.bottomAnchor.constraint(equalTo: container.bottomAnchor, constant: -40).isActive = true
})

--- Video

autolayout.mov

Once you have a look at it and provide feedback, I would appreciate it. Thank you.