CollectionView: Transparency/Background Color for the GroupHeaderTemplate

[rodolfo-sousa]

Would be nice to have the possibility to define the transparency and/or background color of the GroupHeaderTemplate.
Would be nice to be able to add a gradient background to smooth the group area:

I was able to give that look and feel on the bottom of the CollectionView with a Grid and negative top Margin:

PS: I created the same topic in Toolkit... don't know if is something that MAUI should handle it self.