Bump Microsoft.NET.Test.Sdk from 16.8.3 to 16.9.1

Bumps [Microsoft.NET.Test.Sdk](https://github.com/microsoft/vstest) from 16.8.3 to 16.9.1.
- [Release notes](https://github.com/microsoft/vstest/releases)
- [Commits](microsoft/vstest@v16.8.3...v16.9.1)

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

LinkDotNet.EnumValueObject.UnitTests/LinkDotNet.EnumValueObject.UnitTests.csproj

@@ -7,7 +7,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.8.3" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.9.1" />
     <PackageReference Include="MSTest.TestAdapter" Version="2.1.2" />
     <PackageReference Include="MSTest.TestFramework" Version="2.1.2" />
     <PackageReference Include="Shouldly" Version="4.0.3" />