flutter_dropdown 0.0.6+hotfix.2

This does make Flutter Framework complicated dropdown button less complicated

[0.0.6+hotfix.2] -

• Fixed: 'Null' is not a subtype of type '(dynamic) => void'`.

[0.0.6] - Hint became a widget instead of String.

• Hint changed to Widget instead of String (Let me know if need to revert).
• Example app updated

Let me know if this dropdown less complicated with new features. So that, I can keep refactoring this to make it more less complicated.

[0.0.5] - Expanded property.

• Property to make dropdown expanded (isExpanded false by default).

[0.0.4] - Custom widget support.

• Custom widget support for dropdown menu items.

[0.0.3] - Any type dropdown button implementation.

• Create dropdown button for any data items.

[0.0.2] - String only dropdown button implementation.

• Create dropdown button for string items easily.

[0.0.1] - Simple dropdown button.

• Less complex boilerplate code for dropdown button.