FIX: Vertical and Horizontal overflows in toast

[OutdatedGuy]

Fix

• description widget overflows horizontally
• description widget overflows vertically

Changes

• Wrapped contents of toast in Expanded widget to avoid horizontal overflow
• Wrapped contents of toast in SingleChildScrollView widget to avoid vertical overflow

Resolves #66

[koukibadr]

@OutdatedGuy Thanks for your contribution to the package