Bump the test-deps group with 1 update (#774)

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: test-deps
...

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

Author: dependabot[bot]

OSLC4Net_SDK/Directory.Packages.props

@@ -27,7 +27,7 @@
     <!-- Test deps -->
     <PackageVersion Include="Aspire.Hosting.Testing" Version="$(AspireVersion)" />
     <PackageVersion Include="Microsoft.Extensions.Configuration.Json" Version="10.0.8" />
-    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.5.1" />
+    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.6.0" />
     <PackageVersion Include="Verify.TUnit" Version="31.13.2" />
     <PackageVersion Include="NSubstitute" Version="5.3.0" />
     <PackageVersion Include="NSubstitute.Analyzers.CSharp" Version="1.0.17" />