🤖 Bump Microsoft.NET.Test.Sdk from 16.5.0 to 16.9.1 (#3112)

Bumps [Microsoft.NET.Test.Sdk](https://github.com/microsoft/vstest) from 16.5.0 to 16.9.1.
- [Release notes](https://github.com/microsoft/vstest/releases)
- [Commits](https://github.com/microsoft/vstest/compare/v16.5.0...v16.9.1)

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

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

Shadowsocks.Tests/Shadowsocks.Tests.csproj

@@ -9,7 +9,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.8.3" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.9.1" />
     <PackageReference Include="xunit" Version="2.4.1" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.4.3">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>

Shadowsocks.WPF.Tests/Shadowsocks.WPF.Tests.csproj

@@ -9,7 +9,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.8.3" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.9.1" />
     <PackageReference Include="xunit" Version="2.4.1" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.4.3">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>

test/ShadowsocksTest.csproj

@@ -14,7 +14,7 @@
 
   <ItemGroup>
     <PackageReference Include="GlobalHotKeyCore" Version="1.2.0" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.5.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.9.1" />
     <PackageReference Include="MSTest.TestAdapter" Version="2.1.0" />
     <PackageReference Include="MSTest.TestFramework" Version="2.1.0" />
     <PackageReference Include="coverlet.collector" Version="3.0.3">