Feature Request: Add onPanEnd Gesture Support to Color Picker

[egemenongel]

Hello, thank you for your work on this package! I’ve been using it in my projects, and I noticed an opportunity to enhance its functionality by adding support for the onPanEnd gesture.

Adding an onPanEnd callback would enable developers to execute actions when the user finishes selecting a color. I already forked this package to implement this feature. Let me know if you'd like me to contribute a pull request for this feature!