build(nuget): Bump the microsoft group with 1 update (#163)

Bumps Microsoft.NET.Test.Sdk from 18.5.1 to 18.6.0

---
updated-dependencies:
- dependency-name: Microsoft.NET.Test.Sdk
  dependency-version: 18.6.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: microsoft
...

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

Author: dependabot[bot]

JsonApiToolkit.Tests/JsonApiToolkit.Tests.csproj

@@ -11,7 +11,7 @@
     <PackageReference Include="coverlet.collector" Version="10.0.1" />
     <PackageReference Include="Microsoft.AspNetCore.Mvc.Testing" Version="10.0.8" />
     <PackageReference Include="Microsoft.EntityFrameworkCore.InMemory" Version="10.0.8" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.5.1" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.6.0" />
     <PackageReference Include="moq" Version="4.20.72" />
     <PackageReference Include="xunit" Version="2.9.3" />
     <PackageReference Include="xunit.runner.visualstudio" Version="3.1.5" />