Update README.md file for group stacking series KB in .NET MAUI Chart.#5

SaiyathAliFathima merged 1 commit intomasterSyncfusionExamples/How-to-group-stacking-series-in-.NET-MAUI-Chart-SfCartesianChart:masterfrom

Improve-group-stacking-series-kb-in-MauiSyncfusionExamples/How-to-group-stacking-series-in-.NET-MAUI-Chart-SfCartesianChart:Improve-group-stacking-series-kb-in-MauiCopy head branch name to clipboard