Bump Microsoft.NET.Test.Sdk from 16.8.0 to 16.9.1 (#150)

Bumps [Microsoft.NET.Test.Sdk](https://github.com/microsoft/vstest) from 16.8.0 to 16.9.1.
- [Release notes](https://github.com/microsoft/vstest/releases)
- [Commits](microsoft/vstest@v16.8.0...v16.9.1)

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Packages.props

@@ -9,7 +9,7 @@
 		<PackageReference Update="FluentAssertions" Version="[5.10.3]" />
 		<PackageReference Update="Microsoft.AspNet.WebApi.Core" Version="[5.2.7]" />
 		<PackageReference Update="Microsoft.AspNet.WebApi.OwinSelfHost" Version="[5.2.7]" />
-		<PackageReference Update="Microsoft.NET.Test.Sdk" Version="[16.8.0]" />
+		<PackageReference Update="Microsoft.NET.Test.Sdk" Version="[16.9.1]" />
 		<PackageReference Update="Moq" Version="[4.16.1]" />
 		<PackageReference Update="Newtonsoft.Json" Version="[6.0.6]" />
 		<PackageReference Update="NUnit" Version="[3.13.1]" />