Update Microsoft.NET.Test.Sdk to version 16.9.1

Author: 0xced

tests/Serilog.Formatting.Log4Net.Tests.csproj

@@ -12,7 +12,7 @@
     <PackageReference Include="Codecov.MSBuild" Version="1.13.0" />
     <PackageReference Include="coverlet.msbuild" Version="3.0.3" PrivateAssets="all" />
     <PackageReference Include="FluentAssertions" Version="5.10.3" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.8.3" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.9.1" />
     <PackageReference Include="Microsoft.NETFramework.ReferenceAssemblies" Version="1.0.0" />
     <PackageReference Include="PublicApiGenerator" Version="10.2.0" />
     <PackageReference Include="ReportGenerator" Version="4.8.6" />