Changed .NET target to 6.0

PcgsInvUi/App.axaml

@@ -2,11 +2,12 @@
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              x:Class="PcgsInvUi.App"
              xmlns:local="using:PcgsInvUi"
+             xmlns:pcgsInvUi="clr-namespace:PcgsInvUi"
              RequestedThemeVariant="Light">
     <!-- "Default" ThemeVariant follows system theme variant. "Dark" or "Light" are other available options. -->
 
     <Application.DataTemplates>
-        <local:ViewLocator />
+        <pcgsInvUi:ViewLocator />
     </Application.DataTemplates>
 
     <Application.Styles>