Change color and borderColor for unselected stars

[RempelOliveira]

It would be great to have two more parameters to change the background and border color for unselected stars.

[ftvs]

https://pub.dev/packages/flutter_star_rating almost does what you want, but does not have a separate border color for unselected ones. However, both of these libraries are fairly easy to understand and modify.

[maheshmnj]

borderColor: property changes the border color of the unselected star, however it would be great if we could have a filled stars for the unselected one and we could customize it with the unselected color