chore: bump Microsoft.NET.Test.Sdk from 17.5.0 to 17.6.0 in /src

Bumps [Microsoft.NET.Test.Sdk](https://github.com/microsoft/vstest) from 17.5.0 to 17.6.0.
- [Release notes](https://github.com/microsoft/vstest/releases)
- [Changelog](https://github.com/microsoft/vstest/blob/main/docs/releases.md)
- [Commits](microsoft/vstest@v17.5.0...v17.6.0)

---
updated-dependencies:
- dependency-name: Microsoft.NET.Test.Sdk
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

src/UnityNuGet.Tests/UnityNuGet.Tests.csproj

@@ -9,7 +9,7 @@
     <ItemGroup>
         <PackageReference Include="nunit" Version="3.13.3" />
         <PackageReference Include="NUnit3TestAdapter" Version="4.4.2" />
-        <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.5.0" />
+        <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.6.0" />
     </ItemGroup>
 
     <ItemGroup>