Bump Microsoft.NET.Test.Sdk (#317)

Bumps [Microsoft.NET.Test.Sdk](https://github.com/microsoft/vstest) from 16.9.0-preview-20201123-03 to 16.9.0-preview-20210106-01.
- [Release notes](https://github.com/microsoft/vstest/releases)
- [Commits](microsoft/vstest@v16.9.0-preview-20201123-03...v16.9.0-preview-20210106-01)

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Directory.Build.targets

@@ -8,7 +8,7 @@
     <PackageReference Update="Microsoft.Extensions.Configuration.EnvironmentVariables" Version="5.0.0" />
     <PackageReference Update="Microsoft.Extensions.Configuration.Json" Version="5.0.0" />
     <PackageReference Update="Microsoft.Extensions.DependencyInjection" Version="5.0.1" />
-    <PackageReference Update="Microsoft.NET.Test.Sdk" Version="16.9.0-preview-20201123-03" />
+    <PackageReference Update="Microsoft.NET.Test.Sdk" Version="16.9.0-preview-20210106-01" />
     <PackageReference Update="Moq" Version="4.15.2" />
     <PackageReference Update="Npgsql.EntityFrameworkCore.PostgreSQL" Version="5.0.1" />
     <PackageReference Update="octokit" Version="0.48.0" />