Bump the tests group in /src with 2 updates

Bumps the tests group in /src with 2 updates: [xunit](https://github.com/xunit/xunit) and [xunit.runner.visualstudio](https://github.com/xunit/visualstudio.xunit).


Updates `xunit` from 2.8.0 to 2.8.1
- [Commits](xunit/xunit@2.8.0...2.8.1)

Updates `xunit.runner.visualstudio` from 2.8.0 to 2.8.1
- [Release notes](https://github.com/xunit/visualstudio.xunit/releases)
- [Commits](xunit/visualstudio.xunit@2.8.0...2.8.1)

---
updated-dependencies:
- dependency-name: xunit
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: tests
- dependency-name: xunit.runner.visualstudio
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: tests
...

Signed-off-by: dependabot[bot] <[email protected]>

src/Directory.Packages.props

@@ -7,7 +7,7 @@
     <PackageVersion Include="Microsoft.VisualStudioEng.MicroBuild.Core" Version="1.0.0" />
     <!-- Roslyn (version is overridden in Tests) -->
     <PackageVersion Include="Microsoft.CodeAnalysis.Analyzers" Version="3.3.4" />
-    <PackageVersion Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="3.7.0" />
+    <PackageVersion Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="4.9.2" />
     <!-- Analyzers -->
     <PackageVersion Include="Microsoft.VisualStudio.Threading.Analyzers" Version="17.10.48" />
     <PackageVersion Include="Microsoft.CodeAnalysis.CSharp.CodeStyle" Version="4.9.2" />
@@ -21,8 +21,8 @@
     <!-- Tests -->
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.10.0" />
     <PackageVersion Include="System.Reflection.MetadataLoadContext" Version="8.0.0" />
-    <PackageVersion Include="xunit" Version="2.8.0" />
-    <PackageVersion Include="xunit.runner.visualstudio" Version="2.8.0" />
+    <PackageVersion Include="xunit" Version="2.8.1" />
+    <PackageVersion Include="xunit.runner.visualstudio" Version="2.8.1" />
     <PackageVersion Include="Xunit.SkippableFact" Version="1.4.13" />
     <!-- Misc -->
     <PackageVersion Include="Microsoft.Win32.Registry" Version="5.0.0" />