Bump the testing group with 2 updates (#260)

Bumps Microsoft.NET.Test.Sdk from 18.6.0 to 18.7.0
Bumps Microsoft.Testing.Extensions.CodeCoverage from 18.7.0 to 18.8.0

---
updated-dependencies:
- dependency-name: Microsoft.NET.Test.Sdk
  dependency-version: 18.7.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: testing
- dependency-name: Microsoft.Testing.Extensions.CodeCoverage
  dependency-version: 18.8.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: testing
...

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

Author: dependabot[bot]

Directory.Packages.props

@@ -26,7 +26,7 @@
     <PackageVersion Include="xunit.runner.visualstudio" Version="3.1.5" />
     <PackageVersion Include="Microsoft.AspNetCore.Mvc.Testing" Version="10.0.9" />
     <PackageVersion Include="Microsoft.CodeAnalysis.Analyzer.Testing" Version="1.1.4" />
-    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.6.0" />
-    <PackageVersion Include="Microsoft.Testing.Extensions.CodeCoverage" Version="18.7.0" />
+    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.7.0" />
+    <PackageVersion Include="Microsoft.Testing.Extensions.CodeCoverage" Version="18.8.0" />
   </ItemGroup>
 </Project>