Update PopupPageRenderer.cs

updated to use Android Rect due to .Net 5 prerelease

Author: LuckyDucko

Rg.Plugins.Popup/Platforms/Android/Renderers/PopupPageRenderer.cs

@@ -68,7 +68,8 @@ protected override void OnLayout(bool changed, int l, int t, int r, int b)
             var decoreHeight = decoreView.Height;
             var decoreWidht = decoreView.Width;
 
-            var visibleRect = new Rect();
+            var visibleRect = new Android.Graphics.Rect();
+
             decoreView.GetWindowVisibleDisplayFrame(visibleRect);
 
             if (Build.VERSION.SdkInt >= BuildVersionCodes.M)
@@ -244,4 +245,4 @@ private bool IsInRegion(float x, float y, View v)
 
         #endregion
     }
-}
+}