Bump Microsoft.NET.Test.Sdk from 18.8.0 to 18.8.1

---
updated-dependencies:
- dependency-name: Microsoft.NET.Test.Sdk
  dependency-version: 18.8.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

Directory.Packages.props

@@ -16,7 +16,7 @@
     <PackageVersion Include="OpenTelemetry.Exporter.InMemory" Version="1.16.0" />
     <PackageVersion Include="OpenTelemetry.Extensions.Hosting" Version="1.16.0" />
     <PackageVersion Include="Polly" Version="8.7.0" />
-    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.8.0" />
+    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.8.1" />
     <PackageVersion Include="Shouldly" Version="4.3.0" />
     <PackageVersion Include="System.Diagnostics.DiagnosticSource" Version="10.0.9" />
     <PackageVersion Include="System.Text.Json" Version="10.0.9" />