update WindowsSettings plugin to .NET 6

Author: jjw24

Plugins/Flow.Launcher.Plugin.WindowsSettings/Flow.Launcher.Plugin.WindowsSettings.csproj

@@ -1,7 +1,7 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <OutputType>Library</OutputType>
-    <TargetFramework>net5.0-windows</TargetFramework>
+    <TargetFramework>net6.0-windows</TargetFramework>
     <UseWindowsForms>true</UseWindowsForms>
     <CopyLocalLockFileAssemblies>true</CopyLocalLockFileAssemblies>
     <AppendTargetFrameworkToOutputPath>false</AppendTargetFrameworkToOutputPath>